v0.3.0

Added

• Heartbeat locks: holders refresh their lock every 5 s; a lock silent for 60 s is taken over. This also covers
  reused pids, frozen processes and owners on other hosts sharing the repository. A holder never deletes a lock
  that no longer carries its token.
• gate init detects the test command (pytest, npm, go, cargo, unittest) and says why.
• examples/agent_loop.py: reference agent client using only --json, exercised by the test suite.
• e2e_github.py and a weekly/on-demand e2e workflow: batch, crash-after-push recovery and concurrent-push
  scenarios against a real GitHub remote on a throwaway branch.
• Error messages say what to do next (unknown session, nothing committed, dirty worktree).
• mypy now runs with disallow_untyped_defs.

Fixed

• In remote mode the policy was read before fetching, so a gate.toml change pushed to the remote applied one run
  late. A fetch that moves the target now reloads the policy, and submit fetches first.