feat(simulation): sprint 12 server — tier system, sound events, KG access, line previewer

Implements 4 completed tickets + partial progress on 2 more:

- #93 Tier marker components (ActiveSim, BackgroundSim, StateSaved + TierPlugin)
- #138 Information tag schema (ObserverAccess enum in knowledge/types.rs)
- #124 Sound event system (SoundEventEmitter, SoundEventQueue, bridge wiring)
- #193 Line previewer CLI (line_preview binary with filter/explain/sequence modes)
- #94 Active tier simulation (in progress — With<ActiveSim> filters)
- #139 Component-level access control (in progress — filter_by_access)

Updates snapshot fixtures and test golden files for new sound_events field.

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

server/tests/golden/proof_room_tick_10.json

@@ -46,7 +46,7 @@
   "pending_recognitions": [
     {
       "entity_id": 1,
-      "remaining_ticks": 1,
+      "remaining_ticks": 2,
       "total_delay_ticks": 6,
       "x": 16.5,
       "y": 13.5,
@@ -65,8 +65,9 @@
   "player_inventory": [],
   "player_stance": "Sprint",
   "scan_events": [],
+  "sound_events": [],
   "tick": 8,
-  "version": 9,
+  "version": 10,
   "visible_tiles": [
     {
       "tile_kind": "Wall",