Add procedural crowd ambience and radio crackle

- AudioFeedback.start_crowd_bed() builds a 4 s looping AudioStreamWAV at runtime
  (one-pole filtered noise plus a 68/103 Hz drone, seeded) and set_crowd_level()
  maps crowd mood 0..1 to -34..-12 dB, so the street gets louder as it gets
  agitated or panics. The bed starts with the shift and stops at shift end.
- play_radio_open()/play_radio_close() push short filtered-noise bursts; wired to
  opening the radio panel, submitting a report, cancelling, and closing the panel.
- Still asset-free and headless-safe: with a dummy audio server the calls no-op.
  _free_player() returns null before _ready and callers handle it.

Tests/docs
- Headless suite 127 -> 134 (test_audio_feedback.gd).
- New smoke_audio.gd: bed playing, level follows mood events, radio crackles once
  per open/close, bed stops at shift end. Verified windowed (real audio server).
- README, TODO section moved to DONE, MEMORY. Version 0.2.8.

README.md

@@ -28,8 +28,7 @@ The central design goal is simple:
 
 **All releases:** <https://git.allucanget.biz/zwitschi/security-game/releases>
 
-> **Latest: v0.2.7** — NPC theater: guests sit on the steps, tourists and influencers raise a
-> camera, performers play their sign.
+> **Latest: v0.2.8** — procedural crowd ambience driven by crowd mood, and radio crackle.
 > Releases are built automatically when a `vX.Y.Z` tag is pushed
 > (see [`docs/RELEASING.md`](docs/RELEASING.md)); manual builds use
 > `./tools/build_releases.sh`. Installer/AppImage packaging runs in the same pipeline
@@ -253,6 +252,9 @@ godot --headless --path . --script res://src/test/smoke_emergency.gd
 
 # Body-camera timeline smoke: review → timeline → step through → back to review
 godot --headless --path . --script res://src/test/smoke_timeline.gd
+
+# Audio smoke: crowd bed follows mood, radio open/close crackle
+godot --headless --path . --script res://src/test/smoke_audio.gd
 ```
 
 The unit test runner is the project's own lightweight harness (no editor plugin required) so CI can run it without the editor.
@@ -305,7 +307,7 @@ Implemented so far:
 - Godot 4.3 project scaffold, input map, procedural world builder
 - Venue-driven simulation core: `ShiftCoordinator`, `VenueScenario`, `EventScheduler`, `NPCController` + FSM, `AccessVerifier`, `EscalationManager`, `RadioSystem`, `IncidentRecorder`, `ReputationEvaluator`, `CrowdSystem`
 - Three authored scenarios (Hollywood Boulevard building, The Joke Shop, Late Night TV Studio) with access policies, NPC archetypes, and event pools
-- Headless unit tests: **127 passing** (access rules and venue-correct access loadout, escalation, radio cooldown/battery, NPC reaction determinism, door lock, flashlight perception, persistence round-trip, settings round-trip, navmesh, step colliders, skyline alpha, scenario data, full-shift simulation, wand screening, responder dispatch, localization strings, focus cone, action wheel, session shell, PLAN verbs and incident recording, crowd presentation, emergency aftermath, body-camera timeline, NPC theater poses)
+- Headless unit tests: **134 passing** (access rules and venue-correct access loadout, escalation, radio cooldown/battery, NPC reaction determinism, door lock, flashlight perception, persistence round-trip, settings round-trip, navmesh, step colliders, skyline alpha, scenario data, full-shift simulation, wand screening, responder dispatch, localization strings, focus cone, action wheel, session shell, PLAN verbs and incident recording, crowd presentation, emergency aftermath, body-camera timeline, NPC theater poses, audio)
 - Simulation extras: protester archetype, CALL_SOMEONE reaction, door lock/secure mechanic (visual indicator), flashlight with night perception bonus, LATE shift phase reaching the violent-threat event
 - First-person prototype with interaction HUD, access inspection, wand screening, radio report form (incl. emergency hold-to-confirm), dispatched responder avatars, aim-free targeting, venue cycling between all three scenarios, color-coded escalation feedback, procedural audio cues, navigation-mesh NPC paths, JSON-backed localized strings, persisted shift history, debug overlay, and shift review
 - Control pass: focus cone on NPC heads with a billboarded gold ring and name, action wheel (LMB/Space) with de-escalation-first slices, mouse-look freeze while a panel is open, acceleration-based walking, and named input actions (`action_menu`, `confirm`, `cancel`, `inspect`, `wand`)
@@ -320,10 +322,11 @@ Implemented so far:
 - Emergency aftermath: the `evacuation` outcome locks the door and clears the entrance, an emergency call that the situation did not justify opens an investigation and applies the false-report hit, and the shift review names the responder outcome and any investigations
 - Body-camera timeline: the shift review opens a text timeline of every recorded incident event (time, person, action/outcome) that you step through with the arrow keys or buttons. No live 3D replay yet
 - NPC theater: seated guests sit on the steps with bent legs, influencers and tourists raise a camera prop while photographing, performers sway their sign, and filming visitors pan slowly — all once they reach their intent's waypoint
+- Audio: a looping procedural crowd bed (filtered murmur) whose volume follows `CrowdSystem.mood`, plus radio open/close crackle. All generated at runtime, no audio assets, and safe with a dummy audio server
 - Visual polish pass (v0.2.0): phase-based lighting (sun/sky/ambient per shift phase), street lamps with night-mode bulbs and omni lights, glowing marquee signage, crosswalk, planters and low-poly street trees, NPC height/brightness variety, denser routine traffic — day and late-night screenshot sets
 - Assets pass: authored textures in `assets/textures/` (brick facade, concrete, asphalt, awning, skyline, vignette, HUD icons, access-card art) generated by `tools/generate_textures.py`, soft sun shadows, humanoid NPC rigs with archetype props + procedural walk bob and attention head-turn, inspection artifact cards, escalation vignette, mode icons, and a body-camera overlay (REC + shift clock)
 
-Not yet implemented: live 3D body-camera replay, ambience audio, editor-based GUT integration, and crowd performance profiling/LOD (see `TODO.md`).
+Not yet implemented: live 3D body-camera replay, editor-based GUT integration, and crowd performance profiling/LOD (see `TODO.md`).
 
 ### Smoke Test Checklist