fix(server): address PR #23 review — 4 critical bugs, 3 warnings, 11 suggestions

Critical fixes:
- Add PendingRecognitionWire serialization roundtrip test
- Check Option return from delay.cancel() before logging
- InputQueue capacity limit (1000) with drop-oldest and warning
- TODO in observation.rs references ticket #450

Warning fixes:
- Hot-reload guards against invalid/empty content root
- Location header mismatch warning in line pool indexing
- walk_yaml() depth limit (100) against symlink loops
- Consecutive reload failure counter (warns after 5+)

Test additions:
- Negative prerequisite filtering test for monologue lines
- Integration test for pending_recognitions in observer snapshot
- Eavesdrop threshold ordering assertion (Careful < default)

Documentation:
- Playtesting expectation comments on delay constants
- is_pending() scalability note for future NPC cognitive delay
- ID format regex validation in line pool spec
- BTreeMap vs sort() ordering clarification in loader
- Multiplayer TODO in relationships.rs references D-010
- ContentSlug ticket #452 filed for entity slug resolution

394 tests, 0 failures.

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

server/src/content/loader.rs

@@ -93,8 +93,11 @@ fn discover_districts(campaign_path: &Path) -> Vec<PathBuf> {
     if systems_path.is_dir() {
         walk_for_districts(&systems_path, &mut districts);
     }
-    // BTreeMap ordering guarantees deterministic district processing,
-    // but sort the discovery order too for consistency.
+    // Discovery order from fs::read_dir is platform-dependent. Sort the Vec
+    // here so districts load in a deterministic order regardless of OS.
+    // ContentStore.districts uses BTreeMap for deterministic *iteration* later,
+    // but sorted discovery ensures deterministic *load* order (and thus
+    // deterministic ID derivation and log output).
     districts.sort();
     districts
 }