feat(media): add image/video/audio project kinds via od media generate

Introduce non-web media surfaces (image, video, audio) as first-class
project kinds. The unifying contract is "skill workflow + project
metadata tell the agent WHAT to make; one shell command — od media
generate — is HOW bytes are produced", so any code-agent CLI with
shell access can drive it without bespoke tools.

- Frontend: New Project panel gains Image/Video/Audio tabs with model
  picker, aspect/length/duration controls, and audio kind/voice
  selection. Examples and Design Systems tabs gain layered sections.
  FileViewer renders the generated image/video/audio files.
- Shared registry: src/media/models.ts is the single source of truth
  for image/video/audio model IDs, aspects, and defaults — consumed
  by the picker AND the daemon dispatcher.
- Prompts: media-contract.ts is pinned LAST in the system prompt for
  media surfaces so its hard rules (call od media generate, don't
  emit binary in <artifact>, allowed model IDs) win over softer
  earlier wording.
- Daemon: new media.js dispatcher + media-models.js JSON view of the
  registry; cli.js gets the `od media generate` subcommand wired up
  via server.js / projects.js so the daemon writes files back into
  the project dir.
- Skills: audio-jingle, image-poster, video-shortform seed examples
  for the three surfaces.

Made-with: Cursor

daemon/projects.js

@@ -156,6 +156,21 @@ const EXT_MIME = {
   '.gif': 'image/gif',
   '.webp': 'image/webp',
   '.avif': 'image/avif',
+  // Video — covered MIMEs are the formats most generators emit. Browsers
+  // play them via <video> / <audio> in the FileViewer with no transcode.
+  '.mp4': 'video/mp4',
+  '.m4v': 'video/mp4',
+  '.webm': 'video/webm',
+  '.mov': 'video/quicktime',
+  // Audio — music / TTS generators commonly produce mp3 / wav / ogg /
+  // m4a; flac is rarer but cheap to support.
+  '.mp3': 'audio/mpeg',
+  '.wav': 'audio/wav',
+  '.ogg': 'audio/ogg',
+  '.oga': 'audio/ogg',
+  '.m4a': 'audio/mp4',
+  '.flac': 'audio/flac',
+  '.aac': 'audio/aac',
 };
 
 export function mimeFor(name) {
@@ -175,6 +190,10 @@ export function kindFor(name) {
     if (name.startsWith('sketch-')) return 'sketch';
     return 'image';
   }
+  if (['.mp4', '.m4v', '.webm', '.mov'].includes(ext)) return 'video';
+  if (['.mp3', '.wav', '.ogg', '.oga', '.m4a', '.flac', '.aac'].includes(ext)) {
+    return 'audio';
+  }
   if (['.md', '.txt'].includes(ext)) return 'text';
   if (['.js', '.mjs', '.cjs', '.ts', '.tsx', '.json', '.css'].includes(ext)) {
     return 'code';