feat(ui): bind dialogue speaker colors to entity identity (#573)

Maintains Dict[entity_id → Color] in dialogue_box for player conversations.
On first encounter, assigns a round-robin palette color; reuses on subsequent lines.
Eliminates position-based name-hash coloring for player dialogue.

Changes:
- Add _npc_entity_colors dict, _npc_entity_id, _next_npc_color fields
- Add _assign_npc_color(entity_id) — registers palette color on first encounter
- show_dialogue: accept npc_entity_id param, register entity color
- append_line: optional speaker_entity_id/target_entity_id stored in log entries
- append_player_line: pass _npc_entity_id as target_entity_id
- append_dialogue_response: accept entity_id, register, pass to append_line
- _format_entry else branch: look up _npc_entity_colors before name-hash fallback
- main.gd: pass _last_dialogue_npc_id to show_dialogue, speaker_entity_id to append_dialogue_response

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

client/scripts/main.gd

@@ -351,7 +351,8 @@ func _consume_dialogue() -> void:
 	dialogue_box.show_dialogue(
 		dlg.get("npc_name", ""),
 		dlg.get("speech", ""),
-		dlg.get("options", [])
+		dlg.get("options", []),
+		_last_dialogue_npc_id
 	)
 	GameState.current_dialogue = null
 
@@ -385,7 +386,7 @@ func _consume_dialogue_response() -> void:
 	var speaker_color_index: int = dr.get("speaker_color_index", -1)
 	var speaker_name: String = dr.get("speaker_name", _last_dialogue_npc_name)
 	dialogue_box.update_entity_display(speaker_entity_id, speaker_name, speaker_color_index)
-	dialogue_box.append_dialogue_response(speaker_name, dr.get("text", ""))
+	dialogue_box.append_dialogue_response(speaker_name, dr.get("text", ""), speaker_entity_id)
 	GameState.dialogue_response = null
 
 

client/ui/dialogue_box.gd

@@ -45,6 +45,13 @@ var _option_texts: Array[String] = []
 var _option_is_confrontation: Array[bool] = []
 var _npc_name: String = ""
 
+# -- Entity color registry (#573) --
+# Maps entity_id → Color for dialogue participants.
+# Assigned from _npc_colors palette on first encounter; player uses _player_color.
+var _npc_entity_colors: Dictionary = {}  # entity_id -> Color
+var _npc_entity_id: int = -1             # Entity ID of the current player conversation NPC
+var _next_npc_color: int = 0            # Round-robin palette index for client-side assignment
+
 # -- UI state --
 var _active_tween: Tween = null
 var _beat_tween: Tween = null  # D-063: confrontation beat delay
@@ -186,16 +193,22 @@ func _update_layout() -> void:
 ## speaker/target: display names. text: the spoken line.
 ## is_passive: true for overheard NPC-NPC (renders with ┃ prefix + desaturated).
 ## Active conversation entries are pinned (no timeout) while _in_player_conversation.
-func append_line(speaker: String, target: String, text: String, is_passive: bool = false) -> void:
+## speaker_entity_id/target_entity_id: optional entity IDs for stable color lookup (#573).
+func append_line(speaker: String, target: String, text: String, is_passive: bool = false, speaker_entity_id: int = -1, target_entity_id: int = -1) -> void:
 	var pinned := not is_passive and _in_player_conversation
-	_log_entries.append({
+	var entry: Dictionary = {
 		"speaker": speaker,
 		"target": target,
 		"text": text,
 		"is_passive": is_passive,
 		"pinned": pinned,
 		"timestamp_msec": Time.get_ticks_msec(),
-	})
+	}
+	if speaker_entity_id >= 0:
+		entry["speaker_entity_id"] = speaker_entity_id
+	if target_entity_id >= 0:
+		entry["target_entity_id"] = target_entity_id
+	_log_entries.append(entry)
 	_log_dirty = true
 	_ensure_visible()
 
@@ -263,26 +276,32 @@ func on_conversation_ended(_event: Dictionary) -> void:
 
 ## Append the player's chosen response to the log.
 func append_player_line(target_npc: String, text: String) -> void:
-	append_line(PLAYER_NAME, target_npc, text, false)
+	append_line(PLAYER_NAME, target_npc, text, false, -1, _npc_entity_id)
 
 
 ## Append an NPC follow-up line (from dialogue_response).
-func append_dialogue_response(npc_name: String, text: String) -> void:
-	append_line(npc_name, PLAYER_NAME, text, false)
+func append_dialogue_response(npc_name: String, text: String, entity_id: int = -1) -> void:
+	if entity_id >= 0:
+		_assign_npc_color(entity_id)
+	append_line(npc_name, PLAYER_NAME, text, false, entity_id, -1)
 
 
 # -- Active player conversation --
 
 ## Show dialogue with NPC speech and response options.
 ## npc_name: who is speaking. speech: the NPC's line. options: player choices.
-func show_dialogue(npc_name: String, speech: String, options: Array = []) -> void:
+## npc_entity_id: entity ID of the NPC for stable color assignment (#573).
+func show_dialogue(npc_name: String, speech: String, options: Array = [], npc_entity_id: int = -1) -> void:
 	_npc_name = npc_name
+	_npc_entity_id = npc_entity_id
 	_cancel_beat()
 	_in_player_conversation = true
+	if npc_entity_id >= 0:
+		_assign_npc_color(npc_entity_id)
 
 	# Append NPC's line to the log
 	if not speech.is_empty():
-		append_line(npc_name, PLAYER_NAME, speech, false)
+		append_line(npc_name, PLAYER_NAME, speech, false, npc_entity_id, -1)
 
 	# Clear old options and show new ones
 	_clear_options()
@@ -509,8 +528,17 @@ func _format_entry(entry: Dictionary, alpha: float) -> String:
 		# Legacy string-keyed entry (player dialogue, backward compat)
 		speaker = _escape_bbcode(entry.get("speaker", "?"))
 		target = _escape_bbcode(entry.get("target", "?"))
-		speaker_color = _color_for_name(entry.get("speaker", "?"))
-		target_color = _color_for_name(entry.get("target", "?"))
+		# #573: use entity-ID-bound color if available; fall back to name-hash
+		var sp_eid: int = entry.get("speaker_entity_id", -1)
+		var tg_eid: int = entry.get("target_entity_id", -1)
+		if sp_eid >= 0 and _npc_entity_colors.has(sp_eid):
+			speaker_color = _npc_entity_colors[sp_eid]
+		else:
+			speaker_color = _color_for_name(entry.get("speaker", "?"))
+		if tg_eid >= 0 and _npc_entity_colors.has(tg_eid):
+			target_color = _npc_entity_colors[tg_eid]
+		else:
+			target_color = _color_for_name(entry.get("target", "?"))
 		involves_player = (entry.get("speaker", "") == PLAYER_NAME) or (entry.get("target", "") == PLAYER_NAME)
 
 	var text: String = _escape_bbcode(entry.text)
@@ -546,6 +574,21 @@ static func _escape_bbcode(text: String) -> String:
 	return text.replace("[", "[lb]").replace("]", "[rb]")
 
 
+## Assign a palette color to an NPC entity ID on first encounter (#573).
+## Returns the same color on subsequent calls for the same entity ID.
+func _assign_npc_color(entity_id: int) -> Color:
+	if entity_id < 0:
+		return _speech_color
+	if _npc_entity_colors.has(entity_id):
+		return _npc_entity_colors[entity_id]
+	if _npc_colors.is_empty():
+		return _speech_color
+	var color := _enforce_contrast(_npc_colors[_next_npc_color % _npc_colors.size()])
+	_next_npc_color += 1
+	_npc_entity_colors[entity_id] = color
+	return color
+
+
 ## Get a stable color for a character name, with contrast floor enforcement.
 func _color_for_name(char_name: String) -> Color:
 	if char_name == PLAYER_NAME: