feat: local LLM multi-model, session search, cron proactive types, notifications, docs overhaul

Local LLM:
- user_settings.py: per-user hosts/models config (local_llm.json)
- routers/local_llm.py + static/local_llm.html: dedicated settings page
- llm_client.py: local OpenAI-compatible backend via httpx
- config.py: LOCAL_API_URL/KEY/MODEL + per-backend timeouts
- Active model shown near backend toggle (amber hint text)

Memory distillation:
- memory_distiller.py: DISTILL_BACKEND_MID/LONG .env overrides
- scheduler.py + notification.py: notify NC Talk after mid/long distill
- notification.py: outbound channel abstraction (NC Talk, extensible)

Session search:
- routers/files.py: GET /sessions/search?q= with excerpts grouped by date
- static/index.html + app.js: search UI in file sidebar with highlight
- _esc() helper to prevent XSS in search results

Proactive cron:
- cron_runner.py: new job types — message (send directly) and brief (LLM + send)
- Both support optional per-job channel override

Channels:
- routers/nextcloud_talk.py: consolidated using notification._send_nct_message()
- routers/auth.py: local backend status in /auth/status
- routers/chat.py: /backend returns {primary, fallback, local_model} object

UI / UX:
- Copy button for user messages (matching assistant)
- Autocomplete disabled on sensitive form fields
- settings.html: local model section replaced with link to /settings/local

Docs overhaul:
- MASTER.md hub + ARCH__SYSTEM/BACKENDS/PERSONA/CHANNELS/FUTURE.md
- ARCH__Intelligence_Layer.md replaced with redirect table
- CORTEX.md trimmed to vision only; README updated
- OPEN_WEBUI_API.md added to docs/

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

cortex/llm_client.py

@@ -31,6 +31,10 @@ async def cleanup() -> None:
     _active_pgroups.clear()
 
 
+_BACKENDS = ("claude", "gemini", "local")
+_FALLBACK = {"claude": "gemini", "gemini": "claude", "local": "claude"}
+
+
 async def complete(
     system_prompt: str,
     messages: list[dict],
@@ -38,12 +42,12 @@ async def complete(
     max_tokens: int = 2048,
 ) -> tuple[str, str]:
     """Returns (response_text, actual_backend_used)."""
-    if model in ("claude", "gemini"):
+    if model in _BACKENDS:
         primary = model
     else:
         primary = settings.primary_backend
 
-    fallback = "gemini" if primary == "claude" else "claude"
+    fallback = _FALLBACK.get(primary, "claude")
 
     try:
         response = await _dispatch(primary, system_prompt, messages, model)
@@ -65,6 +69,8 @@ async def _dispatch(
 ) -> str:
     if backend == "gemini":
         return await _gemini(system_prompt, messages)
+    if backend == "local":
+        return await _local(system_prompt, messages)
     return await _claude(system_prompt, messages, model)
 
 
@@ -108,6 +114,54 @@ async def _claude(system_prompt: str, messages: list[dict], model: str | None) -
     return await _run(cmd, timeout=settings.timeout_claude, env=env)
 
 
+async def _local(system_prompt: str, messages: list[dict]) -> str:
+    """OpenAI-compatible backend — Open WebUI / Ollama.
+
+    Per-user config (home/{user}/local_llm.json) takes precedence over
+    the server-level .env defaults.
+    """
+    import httpx
+    from persona import _user
+    from user_settings import get_active_local_model
+
+    cfg = get_active_local_model(_user.get())
+    if not cfg:
+        raise RuntimeError("No local model configured — add one at /settings/local")
+
+    api_url = cfg["api_url"]
+    api_key = cfg["api_key"]
+    model   = cfg["model_name"]
+
+    if not api_url:
+        raise RuntimeError("local_api_url not configured — set LOCAL_API_URL in .env or add a host at /settings/local")
+    if not model:
+        raise RuntimeError("local_model not configured — add a model at /settings/local")
+
+    logger.info("local backend: %s @ %s", model, api_url)
+
+    msgs: list[dict] = []
+    if system_prompt:
+        msgs.append({"role": "system", "content": system_prompt})
+    msgs.extend(messages)
+
+    url = api_url.rstrip("/") + "/api/chat/completions"
+    headers: dict[str, str] = {}
+    if api_key:
+        headers["Authorization"] = f"Bearer {api_key}"
+
+    payload = {"model": model, "messages": msgs}
+
+    async with httpx.AsyncClient(timeout=settings.timeout_local) as client:
+        resp = await client.post(url, json=payload, headers=headers)
+        resp.raise_for_status()
+        data = resp.json()
+
+    text = data["choices"][0]["message"]["content"]
+    if not text or not text.strip():
+        raise RuntimeError("Local model returned an empty response")
+    return text.strip()
+
+
 async def _gemini(system_prompt: str, messages: list[dict]) -> str:
     # Gemini CLI spawns MCP child processes that keep stdout pipes open after responding.
     # start_new_session=True puts the whole tree in its own process group so