Analytics dashboards

Add an analytics dashboard to <my app> that tracks <accounts or how my users add theirs>.

On a schedule of <how often>, fetch each account's public profile and engagement, and its posts newest first, stopping at the first post older than <how far back>. The API returns the numbers as they are now, so store a dated snapshot of each one yourself: the history the charts draw is the history you keep.

Then build, per account:
- Follower growth over time.
- Engagement rate over time, and its average and median views, likes and comments per post.
- Its recent posts with their numbers, marking the ones far above or below its usual.

Put accounts from different platforms side by side, using the fields they share. A number a platform doesn't report comes back as null: show it as unknown, never as zero.

Get the data from SocialTap. If the SocialTap MCP server is connected, use its tools; otherwise call the REST API at https://socialtap.dev with the API key from the SOCIALTAP_API_KEY environment variable in the x-api-key header. Read https://socialtap.dev/docs/agents/index.md before the first call. The endpoints, by ID:
- tiktok.profile: GET /v1/tiktok/profile, TikTok Profile API. Docs: https://socialtap.dev/docs/reference/tiktok/profile/index.md
- instagram.profile: GET /v1/instagram/profile, Instagram Profile API. Docs: https://socialtap.dev/docs/reference/instagram/profile/index.md
- youtube.profile: GET /v1/youtube/profile, YouTube Channel API. Docs: https://socialtap.dev/docs/reference/youtube/profile/index.md
- tiktok.posts: GET /v1/tiktok/posts, TikTok Posts API. Docs: https://socialtap.dev/docs/reference/tiktok/posts/index.md
- instagram.posts: GET /v1/instagram/posts, Instagram Posts API. Docs: https://socialtap.dev/docs/reference/instagram/posts/index.md
- youtube.posts: GET /v1/youtube/posts, YouTube Channel Videos API. Docs: https://socialtap.dev/docs/reference/youtube/posts/index.md
- tiktok.engagement: GET /v1/tiktok/engagement, TikTok Engagement API. Docs: https://socialtap.dev/docs/reference/tiktok/engagement/index.md
- instagram.engagement: GET /v1/instagram/engagement, Instagram Engagement API. Docs: https://socialtap.dev/docs/reference/instagram/engagement/index.md
- youtube.engagement: GET /v1/youtube/engagement, YouTube Engagement API. Docs: https://socialtap.dev/docs/reference/youtube/engagement/index.md