bug: NFC broken HW/SW?

implement webui (in OTA mode)
implemented startup and shutdown sound
moved audio playback (and led) to seperate task for better audio latency/stabililty

FW/leo_muziekdoos_esp32/AUDIO_IMPROVEMENTS.md

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+# Audio Handling Improvement Advice
+
+## High Impact
+
+1. Prevent heap growth and fragmentation during song changes.
+- Current behavior allocates new audio source objects for each play request.
+- Improvement: centralize ownership of playback objects and always stop and release old objects before creating new ones.
+
+2. Separate end-of-track from decode error.
+- Current behavior treats any failed loop step as a reason to restart playback.
+- Improvement: classify playback outcomes into Running, Ended, and Error, and only auto-repeat when explicitly enabled.
+
+3. Remove blocking serial work from decoder callbacks.
+- Current behavior prints ID3 data character-by-character and flushes serial from callback context.
+- Improvement: keep callback logging minimal, avoid flush in hot paths, and buffer logs where possible.
+
+4. Model real playback state instead of a single software flag.
+- Current behavior uses one flag for amplifier state and decision flow.
+- Improvement: expose states such as Idle, Starting, Playing, Stopping, Error, and base transitions on decoder status plus requested state.
+
+5. Validate song input before playback starts.
+- Current behavior starts playback when filename is non-empty.
+- Improvement: verify file exists in LittleFS, return reason codes for missing file, invalid path, or decoder start failure.
+
+## Medium Impact
+
+1. Introduce an AudioManager command queue.
+- Use commands like Play(file), Stop, Pause, SetGain.
+- This decouples game logic timing from decoder timing and reduces race-like behavior.
+
+2. Register callbacks once during audio initialization.
+- Avoid repeated callback registration on every play request unless dynamic callback context is required.
+
+3. Make playback policy configurable.
+- Add options such as RepeatMode, ErrorRetryLimit, and RetryBackoffMs in settings.
+
+4. Add runtime telemetry.
+- Track counters for starts, stops, open failures, decode errors, and loop overruns.
+- This improves observability and simplifies field debugging.
+
+## Suggested Implementation Order
+
+1. Add explicit cleanup path for current playback objects.
+2. Introduce a playback result enum and stop auto-restart on all errors.
+3. Reduce callback logging overhead.
+4. Add explicit AudioManager states and update game transitions.
+5. Add configuration flags for repeat and retry policy.
+
+## Affected Areas in Code
+
+- src/audio.cpp
+- src/audio.h
+- src/game.cpp
+- src/config.cpp and data/settings.json (for new policy options)