Bump to v2.3.0: replace polling with SSE stream, fix detector imports

- Add GET /stream SSE endpoint to aggregator.py; state is pushed
  instantly on every change instead of fetched every 2s
- Replace setInterval polling in index.html with EventSource;
  onerror shows the ( ?.?) face and auto-reconnect is handled by
  the browser natively
- Fix ModuleNotFoundError in detectors: inject project root into
  PYTHONPATH when launching subprocesses from kao.py
- Update openapi.yaml, CLAUDE.md, README.md with /stream endpoint
- Remove completed SSE item from TODO.md

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

index.html

@@ -216,8 +216,7 @@
 		<script>
 			const emoteEl = document.getElementById("emote");
 			const messageEl = document.getElementById("message");
-			const POLL_INTERVAL = 2000;
-			const VERSION = "v2.2.0";
+			const VERSION = "v2.3.0";
 
 			// Sound system
 			let audioCtx = null;
@@ -501,20 +500,21 @@
 				document.addEventListener("DOMContentLoaded", initAudio);
 			}
 
-			async function fetchStatus() {
-				try {
-					const response = await fetch("/status");
-					if (!response.ok) throw new Error("Failed to fetch");
-					const data = await response.json();
-					updateDisplay(data);
-				} catch (err) {
-					// Connection lost state
+			function connectStream() {
+				const es = new EventSource("/stream");
+				es.onmessage = (e) => {
+					try {
+						updateDisplay(JSON.parse(e.data));
+					} catch (_) {}
+				};
+				es.onerror = () => {
+					// Connection lost — EventSource will auto-reconnect
 					emoteEl.textContent = "( ?.?)";
 					emoteEl.style.color = "#888888";
 					emoteEl.className = "searching";
 					messageEl.style.color = "#888888";
 					messageEl.textContent = "";
-				}
+				};
 			}
 
 			function updateDisplay(data) {
@@ -541,9 +541,7 @@
 				}
 			}
 
-			// Initial fetch and start polling
-			fetchStatus();
-			setInterval(fetchStatus, POLL_INTERVAL);
+			connectStream();
 		</script>
 	</body>
 </html>