about: fix misleading copy, emphasize experimental + opt-in
- "built locally" wrongly implied the user's machine; it runs on
the server. rewritten to say ken fetches from your PDS and builds
the index on the server.
- added "experimental" upfront.
- clarified the save is opt-in: nothing is written to your repo
unless you click save. the result is stored as a record with
vector blobs, not just "a record."
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>