fix(simulation): address PR #81 review — critical and high-priority issues

Critical fixes:
- storyteller: replace .expect() with guard + log in activation_pass (Hoshe #1)
- content/loader: validate inverted tile_bounds before iteration (Hoshe #C)
- save_io: persist ActivationState on save/load (Tyre #7)

High-priority fixes:
- storyteller: f64 intermediate for observation_time_ticks scoring (Hoshe #A)
- storyteller: deduplicate copresent entities before scoring (Hoshe #B)
- storyteller: skip activation_pass at tick 0 (Hoshe #G)
- storyteller: explicit .before(advance_tick) ordering (Tyre #9)
- save_state: insert EngagementRecord on NPC deserialize (Tyre #10)
- save_io: reset TriangleActivatedQueue + MovementHistoryBuffer on load (Tyre #8)
- debug: validate teleport target walkability (Hoshe #E)
- debug: reject SkipToContamination when tick past delay (Hoshe #F)
- debug: DebugEnabled defaults to cfg!(debug_assertions) (Hoshe #3)
- debug: log when response overwritten (Hoshe #2)
- content/loader: error on tile dimension mismatch (Hoshe #5)
- content/types: DistrictMeta.description optional (Hoshe #D)
- types: version docs updated to v18 (Tyre #1, #2, #3)

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

server/tests/environmental_interaction.rs

@@ -420,6 +420,8 @@ fn minimal_save() -> SaveStateV1 {
         open_doors: vec![],
         modifications: vec![],
         contamination_active: false,
+        activated_count: 0,
+        last_activation_tick: None,
     }
 }
 

server/tests/information_boundaries.rs

@@ -208,6 +208,8 @@ fn save_state_npc_kg_isolation() {
         open_doors: vec![],
         modifications: vec![],
         contamination_active: false,
+        activated_count: 0,
+        last_activation_tick: None,
     };
 
     // Roundtrip: serialize → deserialize.