fix reviewer findings: full unmute reversibility, evidence dedup, fail on mute error
- unmute endpoint now supersedes the turbopuffer spam marker (not just
the platform mute), so phi treats the account as a stranger again
- remove duplicate evidence append — store_exploration_note already
adds evidence_uris
- fail the queue item if mute() throws instead of completing with a
half-done state
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>