Hockey vMix Agent 1.5.3

Changes:
- Connection diagnostics are now split into DNS/TCP, TLS and WebSocket Upgrade stages.
- TCP/TLS/Upgrade stages use short independent timeouts (5 seconds) instead of one opaque 12-second timeout.
- After WebSocket upgrade the Agent waits only 10 seconds for hello.ok and reports this stage explicitly.
- The Agent is considered to have a healthy server route only after hello.ok.
- A failed/slow server attempt can no longer become the preferred server merely because it lasted 5 seconds or more.
- After a real successful session the last healthy server is retried first after a disconnect.
- Reconnect backoff is 2s -> 4s -> 8s -> 15s (max), with manual settings changes resetting the backoff.
- Existing heartbeat, vMix monitoring, Mapping, match assignment and command handling are unchanged.

Expected connection log now looks like:
  Connecting to wss://...
  TCP connected · 70 ms
  TLS handshake OK · 120 ms
  WebSocket upgrade OK · 155 ms
  WebSocket established: ...; waiting for server hello (10s)
  Server registration OK · https://...
  Device registered on server

If the public server is not reachable, the log will identify the stage, for example:
  TCP connect failed after 5000 ms: ...
  TLS handshake failed after 5000 ms: ...
  WebSocket upgrade response failed after 5000 ms: ...
  server did not send hello.ok within 10s

Update:
1. Completely close the current Agent through tray -> Exit.
2. Replace only agent.exe.
3. Keep the existing agent_config.json next to agent.exe. Do NOT replace it.
4. Start Agent again.

Device ID, Device Secret and account pairing remain in agent_config.json and are not changed by this update.