refactor: split tool declarations into domain files + role config UI

tools/__init__.py shrinks from 1,137 → 250 lines. Each domain file now
owns both its callables and its FunctionDeclarations (DECLARATIONS list),
so adding a new tool only touches one file.

New TOOL_CATEGORIES dict exported from __init__ — used by the UI for
grouped tool checkboxes.

Role config UI (Settings → Model Registry → Role Assignments):
- ⚙ button per role expands an inline configure panel
- Textarea for system_append (injected into system prompt for this role)
- Grouped checkboxes for tool allow-list (all checked = no restriction)
- POST /api/models/role-config saves both fields; updates ROLE_CONFIG_DATA
  in-page so re-open reflects current state without a page reload

Backend:
- model_registry.set_role_config() writes system_append + tools to registry
- TOOL_CATEGORIES exported from tools/__init__ for UI rendering
- TOOLS.md header updated: 30 → 39 tools (ae_journal_* and cortex_* additions)

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

cortex/tools/notify.py

@@ -10,6 +10,7 @@ import json
 import logging
 import re
 
+from google.genai import types
 from config import settings
 from persona import get_user
 
@@ -80,3 +81,40 @@ async def nc_talk_send(message: str) -> str:
     except Exception as e:
         logger.warning("nc_talk_send error for %s: %s", username, e)
         return f"Failed to send notification: {e}"
+
+
+DECLARATIONS = [
+    types.FunctionDeclaration(
+        name="email_send",
+        description=(
+            "Send an email from the server's configured SMTP account. Use for delivering "
+            "summaries, reports, reminders, or any content the user wants emailed. "
+            "body is plain text; newlines are preserved."
+        ),
+        parameters=types.Schema(
+            type=types.Type.OBJECT,
+            properties={
+                "to":      types.Schema(type=types.Type.STRING, description="Recipient email address"),
+                "subject": types.Schema(type=types.Type.STRING, description="Email subject line"),
+                "body":    types.Schema(type=types.Type.STRING, description="Plain-text email body"),
+            },
+            required=["to", "subject", "body"],
+        ),
+    ),
+    types.FunctionDeclaration(
+        name="nc_talk_send",
+        description=(
+            "Send a proactive message to the user via their configured notification channel "
+            "(Nextcloud Talk by default). Use this to notify the user of completed background "
+            "tasks, important events, or anything they should know between sessions. "
+            "Requires notification_channel and notification_room set in channels.json."
+        ),
+        parameters=types.Schema(
+            type=types.Type.OBJECT,
+            properties={
+                "message": types.Schema(type=types.Type.STRING, description="The message to send to the user"),
+            },
+            required=["message"],
+        ),
+    ),
+]