perf: reduce 5A chunk timeout to 10s and stop iteration at requested event index

Two improvements to eliminate the ~2-min-per-event wait and unnecessary
full-event-list download when only one event is requested:

1. protocol.py: pass timeout=10.0 to _recv_one in the 5A chunk loop.
   Device responds within ~1s per chunk; 10s gives a safe 10x buffer.
   End-of-stream detection (raw_bytes=1) now fires in 10s instead of 120s,
   cutting ~110s of dead wait per event.

2. client.py: add stop_after_index parameter to get_events(). When set,
   iteration stops immediately after the target event is collected — no
   further 0A/1E/0C/5A/1F cycles for events the caller doesn't need.

3. server.py: pass stop_after_index=index to both /device/event/{idx}
   and /device/event/{idx}/waveform endpoints so a single-event request
   only downloads that one event.

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

minimateplus/protocol.py

@@ -520,7 +520,7 @@ class MiniMateProtocol:
             self._send(build_5a_frame(_BULK_CHUNK_OFFSET, params))
             self._parser.reset()        # reset bytes_fed for accurate per-chunk count
             try:
-                rsp = self._recv_one(expected_sub=rsp_sub, reset_parser=False)
+                rsp = self._recv_one(expected_sub=rsp_sub, reset_parser=False, timeout=10.0)
             except TimeoutError:
                 raw = self._parser.bytes_fed
                 log.warning(