feat(simulation): basic environmental interaction — doors, examine, terminals (#246)

- Add DoorState component tracking is_open and blocking_tile; add
  DoorInteractRequest per-player component consumed by new
  process_door_interaction system (toggles walkability each use)
- Add TerminalInteracted event, TerminalInteractedQueue resource,
  TerminalInteractRequest component, and process_terminal_interaction
  system (emits event on Use verb)
- Add ExamineText(String) component for authored object examine text;
  extend process_examine_interaction with object examine path:
  uses ExamineText if present, falls back to generic string if absent
- Fix: add Without<ObjectType> filter to npc_query in
  process_examine_interaction — previously any entity with TilePosition
  was mis-routed through the NPC text generator
- Add SaveStateV1.open_doors: Vec<StableId> with #[serde(default)]
  for backward-compatible serialization
- Add "Open"/"Close" → DoorInteractRequest and "Use" →
  TerminalInteractRequest dispatch in process_player_input
- 10 integration tests in tests/environmental_interaction.rs covering
  all acceptance criteria: door toggle (both directions), open-to-close,
  invalid target, readable examine (with/without ExamineText), out-of-range,
  terminal event emission, request cleanup, and save state round-trip

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

server/src/simulation/save_state.rs

@@ -94,6 +94,11 @@ pub struct SaveStateV1 {
     /// for deterministic serialization (D-010).
     #[serde(default)]
     pub triangle_states: Vec<TriangleState>,
+    /// Stable IDs of doors that are currently open (#246).
+    /// Doors not in this list are assumed closed on load. Sorted ascending
+    /// for deterministic serialization (D-010).
+    #[serde(default)]
+    pub open_doors: Vec<StableId>,
 }
 
 /// Per-NPC state snapshot for `SaveStateV1`.
@@ -405,6 +410,7 @@ mod tests {
             npc_states: vec![],
             template_references: TemplateReferenceMap::default(),
             triangle_states: vec![],
+            open_doors: vec![],
         }
     }
 
@@ -801,6 +807,7 @@ mod tests {
             npc_states: vec![frozen],
             template_references: TemplateReferenceMap::default(),
             triangle_states: vec![],
+            open_doors: vec![],
         };
 
         let bytes = save.to_bytes().expect("serialize");