Adds ownsTerminalAgent?: boolean to ServerConfig (default true). Wraps the
three shutdown side effects (pkill -f terminal-agent\.ts + 2 safeUnlinkQuiet
calls for terminal-port and terminal-internal-token) inside a single
if (ownsTerminalAgent) block. Embedders (gbrowser phoenix overlay) pass
false to keep their own PTY lifecycle intact across gstack's teardown.
CLI start() call site passes ownsTerminalAgent: true explicitly; static-grep
test in the new test file catches a refactor that drops it.
Strict opt-out: only explicit false flips the gate (cfg.ownsTerminalAgent
=== false ? false : true). Defends against JS callers passing truthy non-bool
values.
Adds __resetShuttingDown test-only export mirroring __resetRegistry. The
module-scoped isShuttingDown latch otherwise silently no-ops a second
shutdown() in the same process.
Drops dead try/catch wrappers around safeUnlinkQuiet inside the new gate —
safeUnlinkQuiet already swallows all errors internally.
New test file (4 cases) stubs both process.exit AND child_process.spawnSync
so a real pkill -f terminal-agent\.ts never fires on the developer machine.
beforeAll/afterAll save and restore real-daemon file contents in the state
dir so the test cannot clobber a running gstack session.