rad issue open --quiet never prints the created issue's id (only a sync
summary), which silently corrupted the stored radicle_id and caused every
issue to be re-mirrored on each pass. Fixed by dropping --quiet and parsing
the id out of the normal output box instead.

Also adds an append-only activity_log table and a small HTTP dashboard
(GitHub-style activity calendar + recent commits list) served alongside
the existing /healthz and /api/status endpoints.

Reworded sentences for clarity and conciseness in the README.