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/routers/nextcloud_talk.py

@@ -1,16 +1,13 @@
 import asyncio
-import hashlib
-import hmac
 import json
 import logging
-import secrets
 
-import httpx
 from fastapi import APIRouter, BackgroundTasks, HTTPException, Request, Response
 
 from auth_utils import get_user_channels
 from context_loader import load_context
 from llm_client import complete
+from notification import _send_nct_message
 from persona import set_context
 from session_logger import log_turn
 from session_store import load as load_session, save as save_session
@@ -40,38 +37,8 @@ def _verify_signature(body: bytes, random_header: str, sig_header: str, secret:
 
 async def _send_reply(conversation_token: str, message: str, nextcloud_url: str, secret: str) -> None:
     """Post a message to Nextcloud Talk as the bot."""
-    url = (
-        f"{nextcloud_url}/ocs/v2.php/apps/spreed/api/v1"
-        f"/bot/{conversation_token}/message"
-    )
-    # NC Talk verifies HMAC over (random + message_text), NOT the raw body.
-    # See BotController::getBotFromHeaders → checksumVerificationService::validateRequest($random, $sig, $secret, $message)
-    body_dict  = {"message": message}
-    body_bytes = json.dumps(body_dict, ensure_ascii=False).encode("utf-8")
-    random_str = secrets.token_hex(32)
-    sig = hmac.new(
-        secret.encode(),
-        (random_str + message).encode("utf-8"),
-        hashlib.sha256,
-    ).hexdigest()
-
-    logger.info("NCT _send_reply → %s (body: %s)", url, body_bytes.decode())
-    try:
-        async with httpx.AsyncClient() as client:
-            resp = await client.post(
-                url,
-                content=body_bytes,
-                headers={
-                    "Content-Type": "application/json",
-                    "OCS-APIRequest": "true",
-                    "X-Nextcloud-Talk-Bot-Random": random_str,
-                    "X-Nextcloud-Talk-Bot-Signature": sig,
-                },
-                timeout=15,
-            )
-        logger.info("NCT reply: %s — %s", resp.status_code, resp.text[:400])
-    except Exception as e:
-        logger.error("NCT reply error: %s", e)
+    logger.info("NCT _send_reply → room %s (%d chars)", conversation_token, len(message))
+    await _send_nct_message(nextcloud_url, secret, conversation_token, message)
 
 
 async def _process_message(