feat(ui): AI-Enhanced Dialogue toggle + hardware detection (#646, D-138)

Implements the full AI-Enhanced Dialogue feature for Sprint 26:

- HardwareDetector autoload (extends Node): three-layer detection —
  Layer 1 RAM classification (pass/marginal/fail, thresholds 2GB/1.6GB),
  Layer 2 TPT benchmark cache (green/yellow/red, thresholds 6/3 t/s),
  Layer 3 degradation monitoring (>40% drop → yellow). load_ai_pref()
  restores toggle state from user://settings.cfg on startup.

- Settings dialog AI section: toggle, colored status dot, status message
  label, testable API (get_ai_dialogue_label_text, set_ai_dialogue_
  hardware_status, is_ai_dialogue_toggle_enabled). Only RAM "fail" greys
  out toggle — player always overrides yellow/red recommendations (D-138).

- GameState.ai_enhanced_dialogue_enabled (default true, opt-out model).
  GameState.settings_response (v20 one-shot settings dump from server).
  apply_snapshot() hydrates ai_enhanced_dialogue_enabled from full dump.

- Protocol v19→v20, settings_response decoding in decode_snapshot().
  Protocol converted to extends Node autoload (enables test has_method).
  encode_change_settings() helper for test inspection.

- InputMapper: CHANGE_SETTINGS, REQUEST_ALL_SETTINGS, DELETE_SETTING.
  SimBridge: wire mappings for all three. RequestAllSettings queued after
  handshake to hydrate client state from server SQLite on connect.
  settings_response carry-forward in receive_bytes().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/data/ui-strings.yaml

@@ -194,6 +194,11 @@ settings:
   text_speed: "Text Speed"
   fullscreen: "Fullscreen"
   language: "Language"
+  # #646: AI-Enhanced Dialogue toggle (D-138)
+  ai_section_header: "AI DIALOGUE"
+  ai_dialogue_toggle: "AI-Enhanced Dialogue"
+  ai_status_checking: "Speed not yet measured — will check on first enable."
+  ai_status_ram_marginal: "Low memory — performance may vary."
 
 # ============================================================
 # CHARACTER SELECTION (if applicable in v0.1)

client/project.godot

@@ -17,6 +17,7 @@ config/icon="res://icon.svg"
 
 [autoload]
 
+Protocol="*res://scripts/protocol/protocol.gd"
 SimBridge="*res://scripts/autoloads/sim_bridge.gd"
 GameState="*res://scripts/autoloads/game_state.gd"
 InputMapper="*res://scripts/autoloads/input_mapper.gd"
@@ -24,6 +25,7 @@ UIStrings="*res://scripts/autoloads/ui_strings.gd"
 FogState="*res://scripts/autoloads/fog_state.gd"
 AudioManager="*res://scripts/autoloads/audio_manager.gd"
 SessionManager="*res://scripts/autoloads/session_manager.gd"
+HardwareDetector="*res://ui/hardware_detector.gd"
 
 [audio]
 

client/scripts/autoloads/game_state.gd

@@ -97,6 +97,17 @@ var pending_load_path: String = ""
 # Default: "detective" — fallback for legacy saves without character.txt.
 var character_archetype: String = "detective"
 
+# #646: AI-Enhanced Dialogue enabled state (D-138).
+# Runtime toggle — true means the LLM re-voicing pipeline should run (server-side).
+# Default: true (opt-out model per D-138 §8). Hardware detector may disable at startup
+# if RAM is insufficient. Persisted to server SQLite via ChangeSettings IPC.
+var ai_enhanced_dialogue_enabled: bool = true
+
+# v20 fields (#627, D-138): settings response from server.
+# One-shot: {kind: "full", settings: [{key, value}]} or {kind: "ack", success, key, error} or null.
+# "full" response hydrates ai_enhanced_dialogue_enabled (server is authoritative for persisted state).
+var settings_response: Variant = null
+
 # v7 fields (#431, D-059/D-060)
 var pending_recognitions: Array = []  # [{entity_id, x, y, z, remaining_ticks, total_delay_ticks}]
 
@@ -328,6 +339,24 @@ func apply_snapshot(snapshot: Dictionary) -> void:
 	else:
 		debug_response = null
 
+	# v20: settings_response (#627, D-138) — one-shot settings ack/dump from server.
+	# "full" kind → iterate settings array and hydrate matching fields.
+	if snapshot.has("settings_response") and snapshot.settings_response is Dictionary:
+		settings_response = snapshot.settings_response
+		var sr: Dictionary = snapshot.settings_response
+		if sr.get("kind") == "full":
+			var sr_settings: Variant = sr.get("settings")
+			if sr_settings is Array:
+				for entry in sr_settings:
+					if not entry is Dictionary:
+						continue
+					if entry.get("key") == "ai_dialogue.enabled":
+						var val: Variant = entry.get("value")
+						if val is Dictionary and val.has("Bool"):
+							ai_enhanced_dialogue_enabled = bool(val["Bool"])
+	else:
+		settings_response = null
+
 	# v14: player_knowledge (#264, D-041) — partial KG dump for journal panel.
 	# Only update when field is present (null means no change, server sends when KG changes).
 	if snapshot.has("player_knowledge") and snapshot.player_knowledge is Dictionary:

client/scripts/autoloads/input_mapper.gd

@@ -25,6 +25,9 @@ enum Action {
 	SAVE_GAME,  # #554: F5 quicksave — sends SaveGame to server with save path
 	LOAD_GAME,  # #554: F6 quickload — sends LoadGame to server with save path
 	DEBUG_COMMAND,  # #581: debug console command dispatch — sends DebugCommandKind to server
+	CHANGE_SETTINGS,      # #646: persist a setting to server SQLite — sends {key, value} to server
+	REQUEST_ALL_SETTINGS, # #646: request full settings dump from server after handshake (unit variant)
+	DELETE_SETTING,       # #646: delete a setting by key from server SQLite (struct variant)
 }
 
 var input_queue: Array[Dictionary] = []

client/scripts/autoloads/sim_bridge.gd

@@ -253,6 +253,12 @@ func _process(delta: float) -> void:
 
 		handshake_complete.emit(server_version)
 		_set_state(ConnectionState.CONNECTED)
+		# #646: Request full settings dump on connect — hydrates GameState.ai_enhanced_dialogue_enabled
+		# from server SQLite so the client reflects the authoritative persisted state (D-138).
+		_outbound_buffer.append({
+			"tick": 0,
+			"action_name": "RequestAllSettings",
+		})
 		return
 
 	if _bridge == null:
@@ -375,6 +381,9 @@ func receive_bytes(bytes: PackedByteArray) -> void:
 		# #554: Carry forward save/load result (one-shot, consumed by main.gd)
 		if snapshot.get("save_result") == null and _last_snapshot.get("save_result") != null:
 			snapshot["save_result"] = _last_snapshot["save_result"]
+		# #646: Carry forward settings_response (one-shot, consumed by game_state apply_snapshot)
+		if snapshot.get("settings_response") == null and _last_snapshot.get("settings_response") != null:
+			snapshot["settings_response"] = _last_snapshot["settings_response"]
 	_last_snapshot = snapshot
 
 # Drain the outbound buffer. Returns raw input entries for batch encoding.
@@ -418,6 +427,12 @@ static func action_enum_to_wire(action: int) -> String:
 			return "LoadGame"  # #554: F6 quickload (D-085)
 		InputMapper.Action.DEBUG_COMMAND:
 			return "DebugCommand"  # #581: debug console command dispatch
+		InputMapper.Action.CHANGE_SETTINGS:
+			return "ChangeSettings"      # #646: persist setting to server SQLite (D-138)
+		InputMapper.Action.REQUEST_ALL_SETTINGS:
+			return "RequestAllSettings"  # #646: unit variant — server sends full settings dump
+		InputMapper.Action.DELETE_SETTING:
+			return "DeleteSetting"       # #646: struct variant — delete setting by key
 		_:
 			push_warning("SimBridge: unknown action enum %s" % action)
 			return ""

client/scripts/protocol/protocol.gd

@@ -1,4 +1,4 @@
-class_name Protocol
+extends Node
 ## MessagePack codec for the Rust↔Godot wire protocol (D-020).
 ##
 ## Encodes/decodes ObserverSnapshot and PlayerInput to match
@@ -11,8 +11,8 @@ class_name Protocol
 
 ## Protocol version — must match server PROTOCOL_VERSION in bridge/types.rs.
 ## Reject snapshots where version != this value.
-## v19: adds character_archetype field to StartupMessage (#588, #587).
-const PROTOCOL_VERSION: int = 19
+## v20: adds settings_response field to ObserverSnapshot (#627, D-138).
+const PROTOCOL_VERSION: int = 20
 
 
 # -- Decode: bytes from server → GDScript types --------------------------------
@@ -270,6 +270,32 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 					"triangle_id": int(raw_ev["triangle_id"]),
 				})
 
+	# v20: settings_response (#627, D-138) — server ack after ChangeSettings / full settings dump
+	# after RequestAllSettings. kind = "full"|"ack". "full": settings array [{key, value}].
+	# "ack": {success: bool, key: String, error: String|null}.
+	var settings_response: Variant = null
+	var raw_sr: Variant = raw.get("settings_response")
+	if raw_sr is Dictionary:
+		var sr_kind: String = str(raw_sr.get("kind", ""))
+		if sr_kind == "full":
+			var sr_settings: Array = []
+			var raw_sr_settings: Variant = raw_sr.get("settings")
+			if raw_sr_settings is Array:
+				for raw_s in raw_sr_settings:
+					if raw_s is Dictionary and raw_s.has("key"):
+						sr_settings.append({
+							"key": str(raw_s["key"]),
+							"value": raw_s.get("value"),
+						})
+			settings_response = {"kind": "full", "settings": sr_settings}
+		elif sr_kind == "ack":
+			settings_response = {
+				"kind": "ack",
+				"success": bool(raw_sr.get("success", false)),
+				"key": str(raw_sr.get("key", "")),
+				"error": raw_sr.get("error"),
+			}
+
 	# v19: current_ticker (#592) — scrolling news headline when in The Last Shift zone.
 	# {id: String, text: String, category: String} or null when player outside bar zone.
 	var current_ticker: Variant = null
@@ -362,6 +388,7 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		"zone_id": zone_id,
 		"triangle_crisis_events": triangle_crisis_events,
 		"current_ticker": current_ticker,
+		"settings_response": settings_response,
 	}
 
 
@@ -548,6 +575,24 @@ static func _encode_action(action_name: String, action_data: Variant) -> Variant
 	return action_name
 
 
+## Encode a ChangeSettings action for the AI-Enhanced Dialogue toggle (#646, D-138).
+## Returns a MessagePack-encoded Vec<PlayerInput> in buffer-entry format
+## (action_name + action_data), suitable for inspection in tests and for
+## queuing via SimBridge._outbound_buffer.
+## The server receives this as a PlayerAction::ChangeSettings variant.
+static func encode_change_settings(enabled: bool) -> PackedByteArray:
+	var entries: Array = [{
+		"tick": 0,
+		"action_name": "ChangeSettings",
+		"action_data": {"ai_enhanced_dialogue": enabled},
+	}]
+	var result = Messagepack.encode(entries)
+	if result.status != null:
+		push_error("Protocol: encode_change_settings failed: %s" % result.status)
+		return PackedByteArray()
+	return result.value
+
+
 ## Decode a PlayerInput from MessagePack bytes (used in tests / echo scenarios).
 ## Returns { "tick": int, "action": { "variant": String, "data": Variant } } or null.
 static func decode_player_input(bytes: PackedByteArray) -> Variant:

client/ui/hardware_detector.gd

@@ -0,0 +1,109 @@
+extends Node
+## Hardware detection autoload for AI-Enhanced Dialogue (D-138, #646).
+##
+## Exposes classification methods for Layer 1 (RAM), Layer 2 (TPT benchmark),
+## and Layer 3 (ongoing TPT degradation monitoring).
+##
+## Loaded as HardwareDetector autoload. Tests access via get_node("/root/HardwareDetector").
+## Settings dialog reads classification strings to configure the toggle UI.
+
+const RAM_PASS_THRESHOLD_MB    := 2000.0
+const RAM_MARGINAL_THRESHOLD_MB := 1600.0
+const TPT_GREEN_THRESHOLD      := 6.0   # tokens/sec — enable silently
+const TPT_YELLOW_THRESHOLD     := 3.0   # tokens/sec — partial pre-voicing note
+const TPT_DEGRADATION_THRESHOLD := 0.4  # fraction — >40% sustained drop → yellow
+
+const BENCHMARK_CACHE_PATH := "user://ai-dialogue-config.json"
+
+
+func _ready() -> void:
+	load_ai_pref()
+
+
+## Layer 1 — RAM classification.
+## Accepts free MB as input; returns "pass" | "marginal" | "fail".
+func classify_ram(free_mb: float) -> String:
+	if free_mb >= RAM_PASS_THRESHOLD_MB:
+		return "pass"
+	elif free_mb >= RAM_MARGINAL_THRESHOLD_MB:
+		return "marginal"
+	else:
+		return "fail"
+
+
+## Layer 2 — TPT benchmark classification.
+## Accepts tokens/sec as input; returns "green" | "yellow" | "red".
+func classify_tpt(tps: float) -> String:
+	if tps >= TPT_GREEN_THRESHOLD:
+		return "green"
+	elif tps >= TPT_YELLOW_THRESHOLD:
+		return "yellow"
+	else:
+		return "red"
+
+
+## Layer 3 — Ongoing degradation classification.
+## D-138 §8: >40% sustained drop from baseline → yellow (not forced disable).
+## Returns "ok" | "yellow".
+func classify_degradation(baseline_tps: float, current_avg_tps: float) -> String:
+	if baseline_tps <= 0.0:
+		return "ok"
+	var drop := (baseline_tps - current_avg_tps) / baseline_tps
+	return "yellow" if drop > TPT_DEGRADATION_THRESHOLD else "ok"
+
+
+## Query the OS for free RAM and return the classification plus the raw MB value.
+## Returns: {classification: String, free_mb: float}
+func check_ram() -> Dictionary:
+	var mem := OS.get_memory_info()
+	# "available" accounts for reclaimable pages (Linux MemAvailable / Windows ullAvailPhys).
+	# Fall back to "free" on platforms that don't provide "available".
+	var free_bytes: int = mem.get("available", mem.get("free", 0))
+	var free_mb: float = float(free_bytes) / (1024.0 * 1024.0)
+	return {"classification": classify_ram(free_mb), "free_mb": free_mb}
+
+
+## Read the cached TPT benchmark result written by the server on first model load.
+## Returns: {tps: float, classification: String} or null if no cache file exists.
+func read_benchmark_cache() -> Variant:
+	if not FileAccess.file_exists(BENCHMARK_CACHE_PATH):
+		return null
+	var f := FileAccess.open(BENCHMARK_CACHE_PATH, FileAccess.READ)
+	if f == null:
+		return null
+	var json := JSON.new()
+	if json.parse(f.get_as_text()) != OK:
+		return null
+	var data: Variant = json.get_data()
+	if not data is Dictionary or not data.has("tps"):
+		return null
+	var tps: float = float(data["tps"])
+	return {"tps": tps, "classification": classify_tpt(tps)}
+
+
+## Load AI dialogue preference from settings.cfg and apply to GameState.
+## Called from _ready() to restore the toggle state across session restarts.
+## Spec: D-138 §8 — toggle persists via ConfigFile (client-local) + server SQLite (#627).
+func load_ai_pref() -> void:
+	var cfg := ConfigFile.new()
+	if cfg.load("user://settings.cfg") != OK:
+		return
+	var enabled: Variant = cfg.get_value("ai_dialogue", "enabled", null)
+	if enabled is bool:
+		GameState.ai_enhanced_dialogue_enabled = enabled
+
+
+## Compose a human-readable status message for the settings dialog.
+## classification: "pass" | "marginal" | "fail" (RAM) or "green" | "yellow" | "red" (TPT).
+## Returns empty string when no message is needed.
+func status_message(ram_classification: String, tpt_classification: String, free_mb: float, tps: float) -> String:
+	if ram_classification == "fail":
+		return "AI-Enhanced Dialogue requires 2 GB of free memory. Your system currently has %.0f MB available. Close other applications and try again, or leave the setting off — the game is complete either way." % free_mb
+	if ram_classification == "marginal":
+		return "Only %.0f MB free — performance may vary. You can still enable it." % free_mb
+	match tpt_classification:
+		"yellow":
+			return "Running at %.0f t/s — pre-voicing will work for main characters and key scenes. Background NPCs may show base text until the queue catches up." % tps
+		"red":
+			return "Running very slowly at %.0f t/s — we recommend leaving this off, but the choice is yours." % tps
+	return ""

client/ui/hardware_detector.gd.uid

@@ -0,0 +1 @@
+uid://hardware_detector_sr

client/ui/settings_dialog.gd

@@ -1,18 +1,24 @@
 extends Control
 
 ## #528: Audio settings dialog — 5-bus volume sliders.
+## #646: AI-Enhanced Dialogue toggle + hardware detection status (D-138).
 ## Opens on OPEN_MENU (ESC) from main.gd. Closes on OPEN_MENU again or CLOSE button.
 ## Volumes persist via AudioManager._save_prefs() on each slider change.
+## AI Dialogue toggle persists via ConfigFile (client-local) + ChangeSettings IPC (server SQLite).
 
 const BG_COLOR := Color(0.05, 0.05, 0.08, 0.90)
 const BORDER_COLOR := Color("#4a9ebb")
 const TEXT_COLOR := Color(0.878, 0.969, 0.98, 1)
 const TITLE_COLOR := Color("#4a9ebb")
+const STATUS_GREEN  := Color("#6bc9a6")
+const STATUS_YELLOW := Color("#e8c547")
+const STATUS_RED    := Color("#c84040")
 const FONT_SIZE := 14
+const FONT_SIZE_SMALL := 11
 
-const BOX_WIDTH := 460
-const BOX_HEIGHT := 376  # +36 for Debug Console row
-const PADDING := 20
+const BOX_WIDTH  := 460
+const BOX_HEIGHT := 500  # +36 debug console, +88 AI dialogue section
+const PADDING    := 20
 const ROW_HEIGHT := 36
 
 # Bus display labels → bus name strings (must match AudioManager BUS_* constants)
@@ -27,8 +33,13 @@ const BUS_ROWS: Array = [
 var _active: bool = false
 var _container: VBoxContainer = null
 
+# #646: AI Dialogue hardware status and toggle node ref — used by testable API methods
+var _ai_hw_status: String = ""  # "pass" | "marginal" | "fail" | "" (not yet checked)
+var _ai_check_node: CheckButton = null
+
 signal closed
 signal debug_console_toggled(enabled: bool)  # #581: debug console enabled/disabled
+signal ai_dialogue_toggled(enabled: bool)    # #646: AI-Enhanced Dialogue enabled/disabled
 
 
 func _ready() -> void:
@@ -138,6 +149,100 @@ func _build_ui() -> void:
 	)
 	debug_hbox.add_child(debug_check)
 
+	# #646: AI Dialogue section divider
+	var ai_divider := Control.new()
+	ai_divider.custom_minimum_size = Vector2(0, 8)
+	_container.add_child(ai_divider)
+
+	var ai_section_label := Label.new()
+	ai_section_label.text = "AI DIALOGUE"
+	ai_section_label.add_theme_font_size_override("font_size", FONT_SIZE - 2)
+	ai_section_label.add_theme_color_override("font_color", TITLE_COLOR)
+	_container.add_child(ai_section_label)
+
+	# #646: Detect hardware and set status
+	var ram_result := HardwareDetector.check_ram()
+	var tpt_cache: Variant = HardwareDetector.read_benchmark_cache()
+	var ram_class: String = ram_result["classification"]
+	var tpt_class: String = "green"
+	var tpt_tps: float = 0.0
+	if tpt_cache != null:
+		tpt_class = tpt_cache["classification"]
+		tpt_tps = tpt_cache["tps"]
+	# Composite status: RAM fail overrides TPT; RAM marginal keeps its own category
+	var hw_status: String
+	if ram_class == "fail":
+		hw_status = "fail"
+	elif ram_class == "marginal":
+		hw_status = "marginal"
+	else:
+		# RAM passes — status follows TPT if benchmarked, else "pass"
+		hw_status = "pass" if tpt_cache == null else tpt_class
+	set_ai_dialogue_hardware_status(hw_status)
+
+	var ai_hbox := HBoxContainer.new()
+	ai_hbox.custom_minimum_size = Vector2(0, ROW_HEIGHT)
+	_container.add_child(ai_hbox)
+
+	var ai_label := Label.new()
+	ai_label.text = get_ai_dialogue_label_text()
+	ai_label.custom_minimum_size = Vector2(200, 0)
+	ai_label.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
+	ai_label.add_theme_font_size_override("font_size", FONT_SIZE)
+	ai_label.add_theme_color_override("font_color", TEXT_COLOR)
+	ai_hbox.add_child(ai_label)
+
+	# Status dot — colored square indicating hardware classification
+	var status_dot := ColorRect.new()
+	status_dot.custom_minimum_size = Vector2(10, 10)
+	status_dot.size_flags_vertical = Control.SIZE_SHRINK_CENTER
+	match _ai_hw_status:
+		"pass", "green":
+			status_dot.color = STATUS_GREEN
+		"marginal", "yellow", "red":
+			status_dot.color = STATUS_YELLOW
+		_:  # "fail"
+			status_dot.color = STATUS_RED
+	ai_hbox.add_child(status_dot)
+
+	var dot_spacer := Control.new()
+	dot_spacer.custom_minimum_size = Vector2(8, 0)
+	ai_hbox.add_child(dot_spacer)
+
+	_ai_check_node = CheckButton.new()
+	_ai_check_node.button_pressed = GameState.ai_enhanced_dialogue_enabled
+	_ai_check_node.disabled = (_ai_hw_status == "fail")
+	ai_hbox.add_child(_ai_check_node)
+
+	# Status message label — only shown when non-empty
+	var status_msg: String = HardwareDetector.status_message(
+		ram_class, tpt_class, ram_result["free_mb"], tpt_tps)
+	var ai_status_label := Label.new()
+	ai_status_label.text = status_msg
+	ai_status_label.add_theme_font_size_override("font_size", FONT_SIZE_SMALL)
+	ai_status_label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
+	ai_status_label.custom_minimum_size = Vector2(BOX_WIDTH - PADDING * 2, 0)
+	match _ai_hw_status:
+		"marginal", "yellow", "red":
+			ai_status_label.add_theme_color_override("font_color", STATUS_YELLOW)
+		"fail":
+			ai_status_label.add_theme_color_override("font_color", STATUS_RED)
+		_:
+			ai_status_label.add_theme_color_override("font_color", TEXT_COLOR)
+	ai_status_label.visible = not status_msg.is_empty()
+	_container.add_child(ai_status_label)
+
+	_ai_check_node.toggled.connect(func(enabled: bool) -> void:
+		GameState.ai_enhanced_dialogue_enabled = enabled
+		_save_ai_pref(enabled)
+		SimBridge.send_input({
+			"action": InputMapper.Action.CHANGE_SETTINGS,
+			"action_data": {"ai_enhanced_dialogue": enabled},
+			"timestamp_msec": Time.get_ticks_msec(),
+		})
+		ai_dialogue_toggled.emit(enabled)
+	)
+
 	# Spacer
 	var spacer := Control.new()
 	spacer.custom_minimum_size = Vector2(0, 8)
@@ -163,6 +268,39 @@ func _destroy_ui() -> void:
 	if _container:
 		_container.queue_free()
 		_container = null
+	_ai_check_node = null  # freed with _container
+
+
+# -- #646: AI Dialogue testable API -------------------------------------------
+
+## Returns the canonical label text for the AI-Enhanced Dialogue toggle (D-138).
+func get_ai_dialogue_label_text() -> String:
+	return "AI-Enhanced Dialogue"
+
+
+## Set the hardware detection status — drives toggle enabled/disabled state.
+## Accepts: "pass" | "marginal" | "fail" (RAM) or "green" | "yellow" | "red" (TPT).
+## Only "fail" (insufficient RAM) disables the toggle. All others leave it enabled —
+## D-138: no hard minimum spec floor; player can always override recommendations.
+func set_ai_dialogue_hardware_status(status: String) -> void:
+	_ai_hw_status = status
+	if _ai_check_node != null:
+		_ai_check_node.disabled = (status == "fail")
+
+
+## Returns true if the AI-Enhanced Dialogue toggle is currently enabled (not greyed out).
+## Only "fail" (RAM below minimum) produces a disabled toggle.
+func is_ai_dialogue_toggle_enabled() -> bool:
+	return _ai_hw_status != "fail"
+
+
+## Persist the AI Dialogue enabled state to the local prefs file.
+## Uses the same settings.cfg as DebugConsole — different section ("ai_dialogue").
+func _save_ai_pref(enabled: bool) -> void:
+	var cfg := ConfigFile.new()
+	cfg.load(DebugConsole.PREFS_PATH)
+	cfg.set_value("ai_dialogue", "enabled", enabled)
+	cfg.save(DebugConsole.PREFS_PATH)
 
 
 func _draw() -> void:
@@ -186,7 +324,7 @@ func _draw() -> void:
 	var font := ThemeDB.fallback_font
 	draw_string(font,
 		box_pos + Vector2(PADDING, PADDING + 18),
-		"AUDIO SETTINGS",
+		"SETTINGS",
 		HORIZONTAL_ALIGNMENT_LEFT, -1, FONT_SIZE + 2, TITLE_COLOR)