feat(notifier): push state events to Smart Home Tablet overlay

Adds a thin HTTP bridge so the tablet at https://tablet.digital-home.site
shows a Siri-style overlay reflecting the current assistant state
(wake / command / response / idle / error). Non-fatal: if the tablet
is offline or TABLET_URL/VOICE_API_KEY are unset, events are silently
skipped and the assistant keeps working.

- satellite/notifier.py — POST /api/voice/event with bearer token,
  reused requests.Session for keep-alive, 1.5s timeout
- satellite/modes.py — emits wake on activation, command after STT,
  response after LLM, idle on timeout
- satellite/llm.py — emits error on gateway connection/timeout/HTTP
- .env.example documents TABLET_URL and VOICE_API_KEY

Tablet side (separate repo smart-home-tablet, commit 51c3d60) exposes
POST /api/voice/event + GET /api/voice/stream (SSE) and renders a
full-screen overlay in components/VoiceOverlay.tsx.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

satellite/modes.py

@@ -4,6 +4,7 @@ from .config import GATEWAY_URL, AGENTS, FOLLOWUP_TIMEOUT, MAX_DURATION, log
 from .audio import record
 from .tts import speak, stop_speaking
 from .llm import ask_agent_stream, is_reset_command, VOICE_SESSION_KEY
+from . import notifier
 
 WAKE_THRESHOLD = float(os.getenv("WAKE_THRESHOLD", "0.5"))
 
@@ -47,15 +48,18 @@ def _conversation_loop(agent_id: str, agent_name: str = "Cosmo"):
         text = record(initial_silence_timeout=timeout)
         if not text:
             print("😴 Тишина, жду активации...\n")
+            notifier.idle()
             return
 
         print(f"📝 Ты → {agent_name}: {text}")
+        notifier.command(text, agent_id)
 
         if _handle_reset(text, agent_id):
             continue
 
         response = ask_agent_stream(text, agent_id=agent_id)
         print(f"🤖 {agent_name}: {response}\n")
+        notifier.response(response, agent_id)
 
 
 def run_with_enter():
@@ -67,6 +71,7 @@ def run_with_enter():
         try:
             input("⏎  Нажми Enter и говори...")
             stop_speaking()  # barge-in
+            notifier.wake("cosmo")
             _conversation_loop("cosmo", "Cosmo")
 
         except KeyboardInterrupt:
@@ -110,7 +115,9 @@ def run_with_porcupine():
                     print(f"PREDICTION cosmo: {cosmo_score:.3f}")
 
                 if cosmo_score > WAKE_THRESHOLD:
+                    print("✅ Услышал 'Космо'!")
                     stop_speaking()  # на случай если TTS ещё играет
+                    notifier.wake("cosmo")
                     stream.stop_stream()
                     _conversation_loop("cosmo", "Cosmo")
                     cosmo_model.reset()