Optimize numpy pipeline, add per-stage timing, and auto-sync LED count

- Eliminate 5 numpy↔tuple conversions per frame in processing hot path:
  map_border_to_leds returns ndarray, inline numpy smoothing with integer
  math, send_pixels_fast accepts ndarray directly
- Fix numpy boolean bug in keepalive check (use `is not None`)
- Add per-stage pipeline timing (extract/map/smooth/send) to metrics API
  and UI with color-coded breakdown bar
- Expose device_fps from WLED health check in API schemas
- Auto-sync LED count from WLED device: health check detects changes and
  updates storage, calibration, and active targets automatically
- Use integer math for brightness scaling (uint16 * brightness >> 8)

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

server/src/wled_controller/main.py

@@ -44,6 +44,7 @@ processor_manager = ProcessorManager(
     capture_template_store=template_store,
     pp_template_store=pp_template_store,
     pattern_template_store=pattern_template_store,
+    device_store=device_store,
 )