chore: clean up dead exports and an unused dependency via fallow

fallow audit --base main flagged 14 exported symbols across the repo
with no external consumers and one unused site dependency (tslib);
fallow fix --yes de-exported the symbols (kept as module-local where
still used internally) and dropped the dependency. Also adds
.fallowrc.json with workspace boundaries and two ignoreExports rules
for files fallow's static reachability check can't otherwise resolve
(daemon/state.ts's registry re-exports, tests/types.ts's shared
fixture types).

Full test suite (376 tests, including live smoke against Together
across every harness) still passes.