feat(desktop): add timeline slider to crop modal with video preview

Add a timeline slider to the crop modal that allows users to scrub through
video frames when selecting crop regions. The implementation includes:

- Timeline slider below crop preview for frame-accurate navigation
- Video element with screenshot fallback using crossfade transition
- Preload strategy: metadata on editor mount, full video on Crop button hover
- Loading indicator whilst video loads
- Multi-segment timeline support with correct segment switching

The video preview replaces the static screenshot when loaded, providing
real-time visual feedback during crop adjustments.

Technical details:
- Video positioned absolute with object-contain to prevent layout shift
- Screenshot remains relative to maintain container dimensions
- localTime calculation fixed to correctly convert timescale units

---

Additional improvements since a1d2ac0:

- fix(general_settings): remove unconditional reset of enable_new_recording_flow
  The flag was being reset to false on every app start, making the setting
  unusable. Users can now toggle between old and new recording flow in settings.

- chore: remove debug telemetry fetch calls from App.tsx, (window-chrome).tsx,
  and setup.tsx. Deleted all #region agent log blocks and hardcoded local
  ingest endpoint calls.

- chore: remove debug console.log statements from context.ts and Suspense
  fallbacks

- fix(ui-solid): correct IconLucideLoader2 import path to use kebab-case
  (loader-2.jsx instead of loader2.jsx)

- fix(crop-modal): correct localTime calculation in currentSegment memo
  Changed from `seg.start + (time - elapsed) * seg.timescale` to
  `seg.start / seg.timescale + (time - elapsed)` for proper time conversion

Author: its-thepoe

apps/desktop/src/routes/editor/context.ts

@@ -12,6 +12,7 @@ import {
 	batch,
 	createEffect,
 	createResource,
+	createRoot,
 	createSignal,
 	on,
 	onCleanup,
@@ -771,8 +772,10 @@ export const [EditorInstanceContextProvider, useEditorInstanceContext] =
 
 			setCanvasControls(controls);
 
-			createEffect(() => {
-				setIsWorkerReady(workerReady());
+			createRoot(() => {
+				createEffect(() => {
+					setIsWorkerReady(workerReady());
+				});
 			});
 
 			ws.addEventListener("open", () => {

apps/desktop/src/routes/editor/cropVideoPreloader.ts

@@ -12,6 +12,11 @@ export function preloadCropVideoMetadata(videoPath: string) {
 	preloadedVideo.preload = "metadata";
 	preloadedVideo.src = convertFileSrc(videoPath);
 	preloadedVideo.muted = true;
+	preloadedVideo.onerror = () => {
+		preloadState = "idle";
+		currentVideoPath = null;
+		preloadedVideo = null;
+	};
 	preloadedVideo.load();
 	preloadState = "metadata";
 }