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/client.py

@@ -228,7 +228,7 @@ class MiniMateClient:
         log.info("count_events: %d event(s) found via 1E/1F chain", count)
         return count
 
-    def get_events(self, full_waveform: bool = False, debug: bool = False) -> list[Event]:
+    def get_events(self, full_waveform: bool = False, debug: bool = False, stop_after_index: Optional[int] = None) -> list[Event]:
         """
         Download all stored events from the device using the confirmed
         1E → 0A → 0C → 5A → 1F event-iterator protocol.
@@ -439,6 +439,15 @@ class MiniMateClient:
                 events.append(ev)
                 idx += 1
 
+                # Early exit: if the caller only wants events up to a specific
+                # index, stop iterating once we've collected it.
+                if stop_after_index is not None and idx > stop_after_index:
+                    log.info(
+                        "get_events: reached stop_after_index=%d — stopping early",
+                        stop_after_index,
+                    )
+                    break
+
             else:
                 # Partial/failed record — skip 5A, just advance with 1F.
                 log.info(