Improve dashboard UX: account search, profile display, always-on replication
- Remove hasReplicateDids gate so ReplicationManager initializes with
empty DID list (allows adding DIDs via dashboard without pre-config)
- Enrich /oauth/status with profile info (avatar, displayName, handle)
from public Bluesky API
- Show account profile in System Overview and Account Connection cards
- Replace plain DID input with account search typeahead in Replicated
DIDs section (uses public app.bsky.actor.searchActorsTypeahead)
- Show avatar + display name + handle for tracked DIDs (async resolved)
- Rename header from "P2PDS Admin" to "P2PDS"