Builds on #72787's current_root guard (cherry-picked with authorship
preserved). Two further hardenings for #72776:
- require the settled cwd and the workspace to share the same common .git
dir (the shape 'git worktree add' produces), so a git workspace visiting
an UNRELATED repo is a browsing visit, not a re-home (repro'd by
Johnny-xuan in the issue thread);
- never reconcile over an explicitly chosen workspace (explicit_cwd),
while a settle-adopted cwd stays followable via a cwd_from_settle
marker cleared by _set_session_cwd / project switch.
Fixes#72776
`_reconcile_session_cwd_from_terminal()` treats a settled terminal cwd in a
different git working tree than the session's workspace as a relocation. But
when the session's workspace is not itself in a git repo, `_git_repo_root_for_cwd(current)`
is None, so the `landed == _git_repo_root_for_cwd(current)` guard never matches
and the FIRST git directory a tool call steps into hijacks the session: its
cwd/git_repo_root flip to that repo, later tools run from the wrong place, and
the repo's AGENTS.md gets injected into an unrelated conversation.
Only reconcile when both the current and settled cwds resolve to valid, differing
git roots. A non-git workspace visiting a git repo to read a file or run a command
is a browsing visit, not a re-home — matching the docstring's own intent that
`cd`-ing away must not re-home the chat. The intended "follow into a worktree"
behavior is unaffected: that path starts from a git checkout, so current_root is
valid there.
Adds a regression test covering a non-git workspace that touches a git repo.
An agent told to work in a fresh git worktree does exactly that — creates
it, cds in, and runs every later command there — but the session stayed
pinned to the checkout it started in. The desktop kept labelling the chat
with the primary branch while all the work landed somewhere else.
The desktop half already existed: session.info carrying a moved cwd runs
followActiveSessionCwd, which refreshes the project tree and scopes the
sidebar into the new project. The backend just never reported the move.
Reconcile the session's cwd against terminal_tool's per-session record at
the end of a turn, when the agent has stopped moving and its recorded cwd
is a stable answer. A plain cd stays what it always was — not a workspace
move — so the reconcile only fires when the recorded cwd sits in a
different git working tree than the session's workspace.