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Delete the hand-authored YAML content pipeline (server/src/content/) superseded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/tests/determinism.rs

@@ -352,11 +352,10 @@ fn gauntlet_deterministic_replay() {
 /// path (select_dialogue_line) which consumes SimRng.
 #[test]
 fn different_seed_produces_different_replay() {
-    use settled_reach_server::content::line_pool::{
+    use settled_reach_server::simulation::line_pool::{
         AccessTier, IndexedDialogueLine, IndexedDialoguePool, LinePoolIndex, Mood, Situation,
-        TrustTier,
+        TrustTier, LinePoolIndexResource,
     };
-    use settled_reach_server::content::LinePoolIndexResource;
     use settled_reach_server::simulation::dialogue::{
         CurrentMood, DialogueCooldownTracker, DialogueProfile, DialogueResponseBuffer,
     };