Tools (write, read, edit, bash) capture cwd at creation time via
createWriteTool(cwd), createReadTool(cwd), etc. When auto-mode
enters a worktree, process.cwd() changes but tools were not
recreated — they continued resolving relative paths against the
original project root.
This caused artifacts to be written to the main project's .gsd/
directory instead of the worktree's .gsd/ directory. The dispatcher
then couldn't find the artifact at the expected worktree path and
retried the unit indefinitely.
Fix: detect cwd change in newSession() and call _buildRuntime()
to recreate tools with the updated cwd. This is a targeted rebuild
that only fires when cwd actually changed (typically once per
auto-mode session when entering/exiting a worktree).
Fixes#633
75e82a4236