refactor(simulation): address PR #32 review — 14 items from Hoshe + Tyre

Hoshe (code quality):
- Remove dead RoomMember component from reset.rs
- Remove execute_reset (dual API trap); plan_reset is sole production path
- .unwrap() → .expect() on reset_plate in setup_gauntlet boot path
- Add 10s read timeout to TCP runtime test (prevents hangs)
- Register player in EntityRegistry in runtime boot test
- Document room_at z-range and corridor overlap assumptions
- Derive entity count from EXPECTED_ENTITY_COUNT constant (was hardcoded 24)
- Add reset plate (49-51) verification to stable_id_ranges_match_spec
- Add debounce exact boundary test (tick 9 rejected, tick 10 accepted)

Tyre (architecture):
- Gate test_world rooms/constants/setup behind "gauntlet" feature (default-on);
  reset module stays always-compiled (production dependency via input system)
- Document setup_gauntlet scheduler bypass for future tracking
- Extract runtime TCP test to content_runtime.rs (separate failure modes)

507 tests passing.

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

server/src/test_world/constants.rs

@@ -156,6 +156,13 @@ pub const ROOMS: &[GauntletRoom] = &[
 
 /// Look up which room a position falls in.
 /// Returns the first room whose bounding box contains the position.
+///
+/// Assumptions:
+///   - All rooms are at z=0 (single-floor Gauntlet). Positions on other
+///     z-levels will never match.
+///   - Room bounding boxes must not overlap (verified by `rooms_do_not_overlap`
+///     test). Corridors are NOT rooms and intentionally fall outside all
+///     bounding boxes — `room_at` returns None for corridor positions.
 pub fn room_at(pos: &TilePosition) -> Option<&'static GauntletRoom> {
     ROOMS.iter().find(|r| {
         pos.x >= r.origin.x
@@ -182,6 +189,17 @@ pub const INTERACTION_GALLERY_STABLE_IDS: (u64, u64) = (24, 28);
 pub const PAUSE_CHAMBER_STABLE_IDS: (u64, u64) = (29, 29);
 pub const DIALOGUE_ROOM_STABLE_IDS: (u64, u64) = (30, 33);
 pub const CROWD_PLAZA_STABLE_IDS: (u64, u64) = (34, 48);
+pub const RESET_PLATE_STABLE_IDS: (u64, u64) = (49, 51);
+
+/// Number of actively-spawned entities in the current Gauntlet build.
+/// Derived from StableId ranges of built rooms + player + reset plates.
+/// Reserved (unbuilt) rooms do not contribute entities.
+pub const EXPECTED_ENTITY_COUNT: usize = 1 // player (StableId 0)
+    + (HUB_STABLE_IDS.1 - HUB_STABLE_IDS.0 + 1) as usize
+    + (OCCLUSION_STABLE_IDS.1 - OCCLUSION_STABLE_IDS.0 + 1) as usize
+    + (INVENTORY_STABLE_IDS.1 - INVENTORY_STABLE_IDS.0 + 1) as usize
+    + (PAUSE_CHAMBER_STABLE_IDS.1 - PAUSE_CHAMBER_STABLE_IDS.0 + 1) as usize
+    + (RESET_PLATE_STABLE_IDS.1 - RESET_PLATE_STABLE_IDS.0 + 1) as usize;
 
 #[cfg(test)]
 mod tests {
@@ -289,6 +307,7 @@ mod tests {
             PAUSE_CHAMBER_STABLE_IDS,
             DIALOGUE_ROOM_STABLE_IDS,
             CROWD_PLAZA_STABLE_IDS,
+            RESET_PLATE_STABLE_IDS,
         ];
         for (i, a) in ranges.iter().enumerate() {
             for (j, b) in ranges.iter().enumerate() {