chore: stage all pending work — caption styling, media server, processing modal, docs, summaries

Includes:
- Extended caption styling (font, shadow, dimmed color, bg toggle)
- Media server, subtitle downloader, VTT parser, processing modal
- Waveform tiers, thumbnail/timeline improvements, transport controls
- Hybrid download model, dependency management, clip export enhancements
- 21 chat summaries, 2 implementation plans, 2 design specs

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/transport/playback.ts

@@ -1,9 +1,19 @@
 import { session } from '$lib/stores/videoSession.svelte';
 
+let _videoEl: HTMLVideoElement | null = null;
+
+export function setVideoElement(el: HTMLVideoElement | null) {
+  _videoEl = el;
+}
+
+function getVideo(): HTMLVideoElement | null {
+  return _videoEl;
+}
+
 export function seekTo(time: number) {
   const clamped = Math.max(0, Math.min(time, session.duration));
   session.currentTime = clamped;
-  const videoEl = document.querySelector('video');
+  const videoEl = getVideo();
   if (videoEl) {
     videoEl.currentTime = clamped;
   }
@@ -14,7 +24,7 @@ export function seekBy(seconds: number) {
 }
 
 export function togglePlayPause() {
-  const videoEl = document.querySelector('video');
+  const videoEl = getVideo();
   if (!videoEl) return;
   if (videoEl.paused) {
     void videoEl.play();
@@ -24,7 +34,7 @@ export function togglePlayPause() {
 }
 
 export function stepFrame(direction: 1 | -1) {
-  const videoEl = document.querySelector('video');
+  const videoEl = getVideo();
   if (videoEl && !videoEl.paused) {
     videoEl.pause();
   }
@@ -44,15 +54,38 @@ export function jumpKeyframe(direction: 1 | -1) {
   }
 }
 
+export function setVolume(v: number) {
+  const videoEl = getVideo();
+  if (videoEl) {
+    videoEl.volume = v;
+    videoEl.muted = false;
+  }
+}
+
+export function setMuted(m: boolean) {
+  const videoEl = getVideo();
+  if (videoEl) {
+    videoEl.muted = m;
+  }
+}
+
+export function getVolume(): number {
+  return getVideo()?.volume ?? 1;
+}
+
+export function getMuted(): boolean {
+  return getVideo()?.muted ?? false;
+}
+
 export function resetShuttleRate() {
-  const videoEl = document.querySelector('video');
+  const videoEl = getVideo();
   if (videoEl) {
     videoEl.playbackRate = 1;
   }
 }
 
 export function adjustShuttle(dir: 1 | -1, shuttleRate: number): number {
-  const videoEl = document.querySelector('video');
+  const videoEl = getVideo();
   if (!videoEl) return shuttleRate;
 
   const nextRate = Math.max(0.25, Math.min(4, shuttleRate + dir * 0.5));