refactor(simulation): remove v0.1 content loading system (#655)

Delete the hand-authored YAML content pipeline (server/src/content/) superseded
by the v0.2 generator-first approach (D-122, D-128). Runtime ECS types that were
co-located with content loading have been extracted to dedicated simulation modules:

- simulation/triangle.rs: TriangleState, TriangleCrisisEventQueue, tick/resolve systems
- simulation/line_pool.rs: LinePoolIndex, AccessTier, TrustTier, Mood, LinePoolIndexResource
- simulation/knowledge_grant.rs: KnowledgeGrant, Prerequisites

Monologue systems (trigger_monologue, trigger_recognition_monologue,
trigger_event_monologue) now use hardcoded fallback lines only; the
ContentStoreResource branch and select_pool_line function are removed.

Deleted: content/{loader,types,line_pool,hot_reload,spawn,instantiation,entanglement,mod}.rs
Deleted: tests/{content_loading,content_runtime,content_scaling,template_instantiation,template_schema}.rs
Deleted: bin/line_preview.rs (v0.1 tool)

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

server/src/bridge/debug.rs

@@ -11,7 +11,7 @@ use bevy_ecs::prelude::*;
 use crate::bridge::types::{
     DebugCommandKind, DebugEnabled, DebugResponsePayload, SnapshotBuffer,
 };
-use crate::content::template::TriangleState;
+use crate::simulation::triangle::TriangleState;
 use crate::knowledge::EntityRegistry;
 use crate::npc::Npc;
 use crate::simulation::conversation::NpcName;

server/src/bridge/types.rs

@@ -17,7 +17,7 @@ pub use crate::simulation::time::{DayPhase, TickRate};
 /// negotiation is unnecessary. Client should reject snapshots with version !=
 /// PROTOCOL_VERSION. New fields use #[serde(default)] only during the migration
 /// period, then the default is removed once both sides are updated.
-pub const PROTOCOL_VERSION: u8 = 19;
+pub const PROTOCOL_VERSION: u8 = 20;
 
 /// Handshake message sent as the very first framed message after connection (#555).
 /// Client reads this before entering the normal tick loop and validates
@@ -80,6 +80,7 @@ pub struct StartupMessage {
 ///           sim_errors (#85, structured error reporting to client).
 /// v18 adds: debug_response (#580, debug console server — command/response wire).
 /// v19 adds: character_archetype on StartupMessage (#587), current_ticker (#591).
+/// v20 adds: settings_response (#627, SQLite settings IPC).
 /// Future fields: ambient sound events, HUD state (D-020 expansion).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ObserverSnapshot {
@@ -210,6 +211,11 @@ pub struct ObserverSnapshot {
     /// None when player is outside the bar or no ticker content is loaded.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub current_ticker: Option<TickerLine>,
+    /// Settings response (#627, SQLite settings IPC).
+    /// Present for exactly one tick after a settings operation completes.
+    /// Client reads to confirm setting changes or to populate the settings UI.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub settings_response: Option<crate::settings::types::SettingsResponseWire>,
 }
 
 /// A single news ticker headline crossing the wire boundary (#591).
@@ -523,6 +529,18 @@ pub enum PlayerAction {
     /// Debug console command (#580). Only processed when `DebugEnabled` is true.
     /// Response delivered via `ObserverSnapshot.debug_response`.
     DebugCommand(DebugCommandKind),
+    /// Change a single setting (#627). Server persists to SQLite and sends
+    /// a `SettingsResponseWire` confirmation in the next snapshot.
+    ChangeSetting {
+        key: String,
+        value: crate::settings::types::SettingValue,
+    },
+    /// Request a full settings dump (#627). Server responds with all current
+    /// settings in `ObserverSnapshot.settings_response`.
+    RequestAllSettings,
+    /// Delete a single setting (#627). Restores the key to its default
+    /// (absent from the database). Confirmation via `settings_response`.
+    DeleteSetting { key: String },
 }
 
 impl PlayerAction {
@@ -839,8 +857,8 @@ pub struct TriangleCrisisEventWire {
     pub tick: u64,
 }
 
-impl From<crate::content::template::TriangleCrisisEvent> for TriangleCrisisEventWire {
-    fn from(e: crate::content::template::TriangleCrisisEvent) -> Self {
+impl From<crate::simulation::triangle::TriangleCrisisEvent> for TriangleCrisisEventWire {
+    fn from(e: crate::simulation::triangle::TriangleCrisisEvent) -> Self {
         Self {
             triangle_id: e.triangle_id.into(),
             role_assignments: e
@@ -912,6 +930,8 @@ pub struct SnapshotBuffer {
     pub pending_save_result: Option<SaveLoadResultWire>,
     /// Pending debug response, consumed once by `compute_observer_snapshot` (#580).
     pub pending_debug_response: Option<DebugResponsePayload>,
+    /// Pending settings response, consumed once by `compute_observer_snapshot` (#627).
+    pub pending_settings_response: Option<crate::settings::types::SettingsResponseWire>,
 }
 
 #[cfg(test)]