Bump to v1.5.0: deduplicate detectors, fix aggregator bugs, fix blocking I/O

- Extract shared send_event/clear_event into detectors/base.py, removing
  ~150 lines of duplication across all 6 detectors
- Fix default aggregator URL from port 5000 to 5100 in all detectors
- Standardize cpu.py and memory.py to use active_alerts set pattern
- Fix immediate emote rotation on startup (last_emote_change = time.time())
- Extract magic numbers to named constants in aggregator
- Protect write_status() with try/except OSError
- Fix notify event ID collision with monotonic counter
- Replace blocking stream_output() with background daemon threads in kao.py

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

kao.py

@@ -11,6 +11,7 @@ import os
 import signal
 import subprocess
 import sys
+import threading
 import time
 from pathlib import Path
 
@@ -59,11 +60,19 @@ class KaoManager:
                 universal_newlines=True,
             )
             print(f"[{name}] Started (PID {process.pid})")
+            # Read output in a background thread to avoid blocking the main loop
+            thread = threading.Thread(target=self._read_output, args=(name, process), daemon=True)
+            thread.start()
             return process
         except Exception as e:
             print(f"[{name}] Failed to start: {e}")
             return None
 
+    def _read_output(self, name, process):
+        """Read and print output from a process in a background thread."""
+        for line in process.stdout:
+            print(f"[{name}] {line.rstrip()}")
+
     def wait_for_aggregator(self, url, timeout=AGGREGATOR_STARTUP_TIMEOUT):
         """Wait for the aggregator to become available."""
         print(f"[aggregator] Waiting for service at {url}...")
@@ -80,15 +89,6 @@ class KaoManager:
         print(f"[aggregator] Timeout waiting for service")
         return False
 
-    def stream_output(self, name, process):
-        """Read and print output from a process (non-blocking)."""
-        if process.stdout:
-            while True:
-                line = process.stdout.readline()
-                if not line:
-                    break
-                print(f"[{name}] {line.rstrip()}")
-
     def get_aggregator_url(self):
         """Get aggregator URL from config port."""
         port = self.config.get("port", 5100)
@@ -135,9 +135,6 @@ class KaoManager:
         for name, info in list(self.processes.items()):
             process = info["process"]
 
-            # Stream any available output
-            self.stream_output(name, process)
-
             # Check if process has exited
             if process.poll() is not None:
                 print(f"[{name}] Exited with code {process.returncode}, restarting in {RESTART_DELAY}s...")