Adds an additive worktree flag to sessions.create so any new chat can run in an
isolated managed worktree of the agent's git workspace, with the branch checked
out and .worktreeinclude provisioning applied. The session's spawnedCwd points at
the matching subdirectory inside the worktree so chat runs, CLI, and the file
browser execute there. agents.list gains workspaceGit (workspace or an ancestor
is a git checkout) to gate the affordance; web sidebar, iOS, and Android expose a
New-Chat-in-worktree action. Uses the method's operator.write scope, but the
.openclaw/worktree-setup.sh step runs only for operator.admin callers since it
executes repo code. Deleting the session, or leaving via a plain New Chat, clears
the cwd and lossless-removes the worktree; idle GC treats recent session activity
as worktree activity so an active session's checkout is never swept.
Live-verified end-to-end on a real gateway; follow-up to #100535 (issue #100534).
Centralized managed worktrees under <state-dir>/worktrees/<repo-fingerprint>/<name>
with branch-per-task (openclaw/<name>), .worktreeinclude provisioning, an optional
.openclaw/worktree-setup.sh repo hook, and a SQLite registry in the shared state DB.
Removal always snapshots the tree (untracked included, gitignored excluded) to
refs/openclaw/snapshots/<id>; restore rebuilds the branch at the original commit with
the snapshot content as uncommitted state. Lossless run-end cleanup, 7-day idle GC for
run-owned worktrees (manual exempt), orphan reconciliation, 30-day snapshot retention.
Surfaces: worktrees.* gateway RPC (operator.admin mutations), openclaw worktrees CLI,
Control UI page, plugin-SDK facade + Workboard kind:"worktree" materialization.
E2E-verified on Testbox: full create->work->remove->restore->gc lifecycle.
