Add classic HUD, auto reload, furniture pathfinding and death flatline

docs/GAMEPLAY-IMPROVEMENTS.md

@@ -0,0 +1,61 @@
+# Classic HUD, automatic reload, furniture navigation, death audio
+
+## HUD
+
+`scripts/game_hud.gd` replaces the debug-style text block with translucent black
+panels and amber classic-FPS typography. Health and magazine numbers are large,
+low health (<=25) and low ammo (<=5) turn red. Reload status is explicit; wave,
+score and grenade cooldown are compact at top center. Panels are above touch
+controls; every HUD Control ignores mouse events so the Web start gesture works.
+Desktop instructions are hidden in touch mode. `30 / 30` means loaded/max magazine,
+not a fictional reserve-ammo counter (reloads remain unlimited).
+
+## Automatic reload
+
+The last shot triggers `start_reload()` immediately. An empty magazine detected in
+physics also triggers it. Guarded against duplicate requests, full magazines and
+death. Existing duration1.57s and reload sounds remain; no refill after death.
+Manual R and touch reload are unchanged.
+
+## Shared grid navigation on the room's XZ floor
+
+`scripts/room_navigation.gd` builds a shared35x35 AStarGrid2D with0.5m cells.
+Obstacles come from `office_props` box collisions transformed into world-space
+XZ rectangles (including rotated chairs). Rectangles are expanded0.60m to protect
+the zombie capsule radius0.35m plus grid/edge margin. Diagonals are allowed only
+when both adjacent cells are free. Grid setup calls update BEFORE solid flags,
+since update clears them.
+
+Targets/start cells inside expanded obstacles are snapped to the nearest free
+cell. Each zombie caches direct visibility or an A* route, refreshing approximately
+every0.55–0.67s with staggered intervals rather than every physics frame. Clear
+routes use direct pursuit; blocked routes follow waypoints. Entry window tween,
+animations, gravity, attack range and corpse behavior remain unchanged.
+Melee also checks a world-geometry ray below desk-top height: chest-high rays can
+pass over tables even when the actors cannot physically approach each other.
+
+This map is for static furniture: moved/new props require rebuilding it. Existing
+body collisions still separate zombies, but this is not a full crowd avoidance
+solver. No mobile FPS guarantee is made. The algorithm uses the existing simple
+flat room and does not require runtime navmesh baking or native extensions.
+
+Reference: https://docs.godotengine.org/en/stable/classes/class_astargrid2d.html
+
+## Death sound
+
+Copied the ORIGINAL local Half-Life `valve/sound/fvox/flatline.wav` to
+`assets/audio/fvox/flatline.wav`, no source modification. SHA256:
+`6fc00ca83a1310b8ff373a77ff895c5396c35416c00a974a0fa55b3fb14bd772`.
+Duration3.994s, mono11025Hz. Played once at-9dB on death alongside the existing
+player vocal; nonpositional so it remains audible through the camera fall.
+
+## Verification
+
+`tools/test_gameplay_improvements.gd`: HUD values/colors/touch hints, immediate
+last-shot reload, duplicate-request guard, physical pursuits around both desks,
+chairs (including rotated chair) and barrel, blocked melee through desk,
+idempotent flatline and no refill after death. Passed headless and with real
+PulseAudio output. All eight prior test suites pass. Touch screenshot of new HUD
+inspected via test_office_atmosphere --screenshot --touch.
+Existing test-shutdown resource-in-use warnings remain. Device touch feel and
+smartphone performance still need real-device validation.

docs/OFFICE-ATMOSPHERE.md

@@ -3,8 +3,8 @@
 `scripts/office_atmosphere.gd` adds two desks, three chairs and a metal fire barrel.
 Props use low-poly primitives with simple static collisions on world layer 1.
 Positions avoid the four cardinal entry corridors and the central combat space.
-The zombies still use their existing direct pursuit, not a new pathfinding system;
-props can obstruct arbitrary paths when the player hides behind them.
+Zombies now route around furniture using the shared XZ grid described in
+`GAMEPLAY-IMPROVEMENTS.md`; static collision bounds feed the navigation map.
 
 The central ceiling OmniLight was removed. Ambient energy is 0.12 with a cool blue
 color, preserving silhouette readability rather than total darkness. Two warm desk
@@ -40,4 +40,4 @@ Three screenshots `/tmp/zombie-office-{0,1,2}.png` inspected, including the barr
 All seven prior suites pass: health/sky, music, grenade, waves, death, damage, touch.
 Existing resource-in-use warnings at test shutdown remain. Actual smartphone
 performance has not been measured; this is a small light/particle budget, not an
-FPS guarantee. Keep testing arbitrary zombie routes around the new obstacles.
+FPS guarantee. Physical furniture-pursuit tests are in `test_gameplay_improvements.gd`.

docs/WEB-DEPLOY.md

@@ -1,5 +1,13 @@
 # Web build and compressed deployment
 
+## Gameplay improvements release: 7ebf03fe3c88be15
+
+See `docs/GAMEPLAY-IMPROVEMENTS.md`: amber HUD, automatic reload, shared furniture
+pathfinding and original Half-Life flatline. PCK 3,972,620 bytes; gzip payload total
+12,424,176 bytes. Previous releases retained; root backup `index-before-gameplay.html`.
+Serial staging import workaround retained.
+
+
 ## Office atmosphere release: fd65770c62e811fe
 
 See `docs/OFFICE-ATMOSPHERE.md`: two desks, three chairs, two desk lamps and