Add audio sources as first-class entities, add mapped CSS type, simplify target editor for mapped sources

- Audio sources moved to separate tab with dedicated CRUD API, store, and editor modal
- New "mapped" color strip source type: assigns different CSS sources to distinct LED sub-ranges (zones)
- Mapped stream runtime with per-zone sub-streams, auto-sizing, hot-update support
- Target editor auto-collapses segments UI when mapped CSS is selected
- Delete protection for CSS sources referenced by mapped zones
- Compact header/footer layout

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

server/src/wled_controller/api/__init__.py

@@ -11,6 +11,7 @@ from .routes.pattern_templates import router as pattern_templates_router
 from .routes.picture_targets import router as picture_targets_router
 from .routes.color_strip_sources import router as color_strip_sources_router
 from .routes.audio import router as audio_router
+from .routes.audio_sources import router as audio_sources_router
 from .routes.profiles import router as profiles_router
 
 router = APIRouter()
@@ -22,6 +23,7 @@ router.include_router(pattern_templates_router)
 router.include_router(picture_sources_router)
 router.include_router(color_strip_sources_router)
 router.include_router(audio_router)
+router.include_router(audio_sources_router)
 router.include_router(picture_targets_router)
 router.include_router(profiles_router)