feat: Update local agent documentation to reflect changes in user_id and session_id handling; add marketing strategy document; update skills-lock.json with new Remotion best practices; update website subproject commit.

.claude/skills/remotion-best-practices/rules/voiceover.md

@@ -0,0 +1,99 @@
+---
+name: voiceover
+description: Adding AI-generated voiceover to Remotion compositions using TTS
+metadata:
+  tags: voiceover, audio, elevenlabs, tts, speech, calculateMetadata, dynamic duration
+---
+
+# Adding AI voiceover to a Remotion composition
+
+Use ElevenLabs TTS to generate speech audio per scene, then use [`calculateMetadata`](./calculate-metadata) to dynamically size the composition to match the audio.
+
+## Prerequisites
+
+By default this guide uses **ElevenLabs** as the TTS provider (`ELEVENLABS_API_KEY` environment variable). Users may substitute any TTS service that can produce an audio file.
+
+If the user has not specified a TTS provider, recommend ElevenLabs and ask for their API key.
+
+Ensure the environment variable is available when running the generation script:
+
+```bash
+node --strip-types generate-voiceover.ts
+```
+
+## Generating audio with ElevenLabs
+
+Create a script that reads the config, calls the ElevenLabs API for each scene, and writes MP3 files to the `public/` directory so Remotion can access them via `staticFile()`.
+
+The core API call for a single scene:
+
+```ts title="generate-voiceover.ts"
+const response = await fetch(
+  `https://api.elevenlabs.io/v1/text-to-speech/${voiceId}`,
+  {
+    method: "POST",
+    headers: {
+      "xi-api-key": process.env.ELEVENLABS_API_KEY!,
+      "Content-Type": "application/json",
+      Accept: "audio/mpeg",
+    },
+    body: JSON.stringify({
+      text: "Welcome to the show.",
+      model_id: "eleven_multilingual_v2",
+      voice_settings: {
+        stability: 0.5,
+        similarity_boost: 0.75,
+        style: 0.3,
+      },
+    }),
+  },
+);
+
+const audioBuffer = Buffer.from(await response.arrayBuffer());
+writeFileSync(`public/voiceover/${compositionId}/${scene.id}.mp3`, audioBuffer);
+```
+
+## Dynamic composition duration with calculateMetadata
+
+Use [`calculateMetadata`](./calculate-metadata.md) to measure the [audio durations](./get-audio-duration.md) and set the composition length accordingly.
+
+```tsx
+import { CalculateMetadataFunction, staticFile } from "remotion";
+import { getAudioDuration } from "./get-audio-duration";
+
+const FPS = 30;
+
+const SCENE_AUDIO_FILES = [
+  "voiceover/my-comp/scene-01-intro.mp3",
+  "voiceover/my-comp/scene-02-main.mp3",
+  "voiceover/my-comp/scene-03-outro.mp3",
+];
+
+export const calculateMetadata: CalculateMetadataFunction<Props> = async ({
+  props,
+}) => {
+  const durations = await Promise.all(
+    SCENE_AUDIO_FILES.map((file) => getAudioDuration(staticFile(file))),
+  );
+
+  const sceneDurations = durations.map((durationInSeconds) => {
+    return durationInSeconds * FPS;
+  });
+
+  return {
+    durationInFrames: Math.ceil(sceneDurations.reduce((sum, d) => sum + d, 0)),
+  };
+};
+```
+
+The computed `sceneDurations` are passed into the component via a `voiceover` prop so the component knows how long each scene should be.
+
+If the composition uses [`<TransitionSeries>`](./transitions.md), subtract the overlap from total duration: [./transitions.md#calculating-total-composition-duration](./transitions.md#calculating-total-composition-duration)
+
+## Rendering audio in the component
+
+See [audio.md](./audio.md) for more information on how to render audio in the component.
+
+## Delaying audio start
+
+See [audio.md#delaying](./audio.md#delaying) for more information on how to delay the audio start.