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/simulation/input.rs

@@ -14,6 +14,10 @@ use crate::simulation::time::{SimulationTime, TickRate};
 use bevy_ecs::prelude::*;
 use std::collections::VecDeque;
 
+/// Maximum number of inputs the queue will hold before dropping oldest.
+/// Prevents unbounded memory growth from input flooding.
+pub const INPUT_QUEUE_CAPACITY: usize = 1000;
+
 /// Queue of pending player inputs, ordered by tick
 #[derive(Resource, Debug, Default)]
 pub struct InputQueue {
@@ -24,6 +28,7 @@ impl InputQueue {
     /// Add a new input to the queue.
     /// Inputs must be pushed in tick order for deterministic processing.
     /// Panics in debug builds if tick ordering is violated.
+    /// Drops oldest inputs when capacity is exceeded.
     pub fn push(&mut self, input: PlayerInput) {
         debug_assert!(
             self.queue.back().is_none_or(|last| last.tick <= input.tick),
@@ -31,6 +36,14 @@ impl InputQueue {
             self.queue.back().map_or(0, |last| last.tick),
             input.tick,
         );
+        if self.queue.len() >= INPUT_QUEUE_CAPACITY {
+            let dropped = self.queue.pop_front();
+            tracing::warn!(
+                "InputQueue at capacity ({}), dropping oldest input (tick={})",
+                INPUT_QUEUE_CAPACITY,
+                dropped.map_or(0, |d| d.tick),
+            );
+        }
         self.queue.push_back(input);
     }