atproto git client

fix(lock): take the store lock on jacquard's writes too master

`SessionStore` reached `write_store_at` directly, so most writes to sessions.json were atomic and unlocked, and a whole-file rewrite can drop another process's session. Taking it unconditionally deadlocks inside a refresh, so `take_or_inherit` keyed on the task id closes both. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>


+230 -35
4 changed files