feat: port remotion-video-creation skill (29 rules), restore missing files

New skill:
- remotion-video-creation: 29 domain-specific Remotion rules covering 3D/Three.js,
  animations, audio, captions, charts, compositions, fonts, GIFs, Lottie,
  measuring, sequencing, tailwind, text animations, timing, transitions,
  trimming, and video embedding. Ported from personal skills.

Restored:
- autonomous-agent-harness/SKILL.md (was in commit but missing from worktree)
- lead-intelligence/ (full directory restored from branch commit)

Updated:
- manifests/install-modules.json: added remotion-video-creation to media-generation
- README.md + AGENTS.md: synced counts to 139 skills

Catalog validates: 30 agents, 60 commands, 139 skills.

skills/remotion-video-creation/rules/get-audio-duration.md

@@ -0,0 +1,58 @@
+---
+name: get-audio-duration
+description: Getting the duration of an audio file in seconds with Mediabunny
+metadata:
+  tags: duration, audio, length, time, seconds, mp3, wav
+---
+
+# Getting audio duration with Mediabunny
+
+Mediabunny can extract the duration of an audio file. It works in browser, Node.js, and Bun environments.
+
+## Getting audio duration
+
+```tsx
+import { Input, ALL_FORMATS, UrlSource } from "mediabunny";
+
+export const getAudioDuration = async (src: string) => {
+  const input = new Input({
+    formats: ALL_FORMATS,
+    source: new UrlSource(src, {
+      getRetryDelay: () => null,
+    }),
+  });
+
+  const durationInSeconds = await input.computeDuration();
+  return durationInSeconds;
+};
+```
+
+## Usage
+
+```tsx
+const duration = await getAudioDuration("https://remotion.media/audio.mp3");
+console.log(duration); // e.g. 180.5 (seconds)
+```
+
+## Using with local files
+
+For local files, use `FileSource` instead of `UrlSource`:
+
+```tsx
+import { Input, ALL_FORMATS, FileSource } from "mediabunny";
+
+const input = new Input({
+  formats: ALL_FORMATS,
+  source: new FileSource(file), // File object from input or drag-drop
+});
+
+const durationInSeconds = await input.computeDuration();
+```
+
+## Using with staticFile in Remotion
+
+```tsx
+import { staticFile } from "remotion";
+
+const duration = await getAudioDuration(staticFile("audio.mp3"));
+```