Claude Code Studio v7.12.0

Worktree isolation reaches every door that creates a unit of work, and a worktree
is no longer removed while something still lives in it.

Every creator is isolated, or deliberately is not

• Telegram was invisible to isolation. It creates sessions and tasks with direct
  SQL, so a Telegram chat wrote into the project root while a browser chat in the
  same project wrote into its own worktree — and the browser's merge landed on top
  of Telegram's uncommitted work. Nine creators now isolate, including three in the
  forum module that reach the database through shared prepared statements.
• Chains: all four doors. REST, MCP create_chain, and both dispatch paths mint
  through one helper, so a project can no longer hold isolated and unisolated chains
  side by side. A chain shares ONE worktree across its members and merges once, when
  the last member finishes; a recurring chain gets a fresh tree per cycle.
• Three sites that CONTINUE work inherit rather than mint. A compact, the sidecar
  session a task runs under, and a JSON import were each dropping the metadata that
  says which tree they belong to — so they read as unisolated while living inside an
  isolated tree, and the file browser answered 403 for them.

A worktree is not removed while a unit still lives in it

• Four removal sites are now guarded: the post-merge cleanup, task delete, session
  delete and bulk delete. Previously each of them could delete the tree a live
  session was still working in, and force: true reported nothing when it did.
• A failed commit stops the merge and the removal. The chain merge swallowed a
  commitAll failure, so the merge carried only what was already committed and the
  removal deleted the rest — data loss on a path where nothing had gone wrong.
• The in-use check fails SAFE: an error keeps the tree. A stale worktree is
  recoverable; a deleted live one is not.
• A recurring chain no longer re-arms over a conflict, which would abandon a branch
  whose commits are real work.

Fixed along the way

• Chain members stayed visible under their own project: the chain listing resolves a
  project with COALESCE(git_root, workdir) the way the task listing already did.
• An isolated parent no longer gets 403 on the result of the task it just created —
  get_task_result and cancel_task compared a raw workdir.
• The WS dispatch door degrades to the project root only when the host has no git;
  every other failure is reported instead of silently creating an unisolated chain.

Known limit

A chain whose member is cancelled or fails never reaches "all done", so its tree and
branch persist and its recurrence does not re-arm. The work is committed on the
branch — this is a leak and a stalled schedule, not lost work — and it needs a
terminal-state policy rather than a patch.