Fix PriorityQueue crash when protobuf messages are compared as tiebreakers ...

Python's heapq compares all tuple elements if earlier ones are equal.
Using timestamp as the second key means two rapidly queued messages at
the same millisecond trigger comparison of the protobuf message objects,
which don't support '<'. Replace timestamp with a monotonic sequence
counter so the message object is never reached in the comparison.

Fixes: Reader thread FATAL exception: '<' not supported between instances
of 'ClientTaskMessage' and 'ClientTaskMessage'

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add token self-recovery to survive auth failures without SSH access ...

- GrpcMeshTransport: on handshake rejection, calls /api/v1/agent/token-sync
  using stable secret_key to fetch fresh invite_token and retries handshake.
  Persists recovered token to all known config file locations.
- agent_update.py: new /token-sync endpoint (auth: hub SECRET_KEY header).
- node.py: wire hub_http_url + secret_key into GrpcMeshTransport constructor.
- reinstall_windows_agent.ps1: idempotent all-in-one reinstall script —
  kills competing python processes, disables ghost startup bat, syncs config,
  optionally updates token, re-registers task with RestartCount=3.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

refactor done