fix: bound WebSocket reconnect attempts

[luojiyin1987]

Summary

• Move live WebSocket reconnects out of the close callback.
• Add exponential backoff with a 30-second delay cap.
• Limit live WebSocket reconnects to five attempts per process.
• Stop reconnecting after KeyboardInterrupt or SystemExit.
• Retry only expected WebSocket and operating system connection errors.
• Do not retry setup, parsing, signature, or program errors.
• Apply auto_reconnect to both direct-message connection errors.

Retry policy

The retry budget covers the full start_ws() call. A successful connection does not reset it. This keeps a hard upper limit on reconnects.

Verification

• Run python -m unittest discover -s tests -v.
• Run seven reconnect policy tests.
• Compile all changed Python modules with py_compile.
• Verify user interrupts stop the reconnect loop.
• Verify remote closes still use bounded backoff.
• Verify setup and program errors propagate without retries.
• Verify auto_reconnect=False blocks both connection error types.

Closes #79