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/reminders.py

@@ -16,6 +16,7 @@ import asyncio
 from datetime import datetime, timezone
 from pathlib import Path
 
+from google.genai import types
 from persona import persona_path
 
 
@@ -124,3 +125,55 @@ async def reminders_remove(index: int) -> str:
 
 async def reminders_clear() -> str:
     return await asyncio.to_thread(_reminders_clear)
+
+
+DECLARATIONS = [
+    types.FunctionDeclaration(
+        name="reminders_add",
+        description=(
+            "Add a new reminder to REMINDERS.md. Reminders are automatically surfaced "
+            "in your context at the start of each session (Tier 2+). "
+            "Use this when the user asks you to remember something, follow up on something, "
+            "or surface a note at the next session."
+        ),
+        parameters=types.Schema(
+            type=types.Type.OBJECT,
+            properties={
+                "text": types.Schema(type=types.Type.STRING, description="The reminder text to add"),
+                "label": types.Schema(type=types.Type.STRING, description="Optional heading for this reminder (e.g. 'Follow up on NC Talk'). Defaults to current timestamp."),
+            },
+            required=["text"],
+        ),
+    ),
+    types.FunctionDeclaration(
+        name="reminders_list",
+        description=(
+            "Read all current pending reminders from REMINDERS.md. "
+            "Use this to check what reminders are queued before adding duplicates, "
+            "or to show the user what's pending."
+        ),
+        parameters=types.Schema(type=types.Type.OBJECT, properties={}),
+    ),
+    types.FunctionDeclaration(
+        name="reminders_remove",
+        description=(
+            "Remove a single reminder by its number. "
+            "Call reminders_list first to get the numbered list, then pass the number of the reminder to remove."
+        ),
+        parameters=types.Schema(
+            type=types.Type.OBJECT,
+            properties={
+                "index": types.Schema(type=types.Type.INTEGER, description="The number of the reminder to remove (1 = first item in reminders_list output)."),
+            },
+            required=["index"],
+        ),
+    ),
+    types.FunctionDeclaration(
+        name="reminders_clear",
+        description=(
+            "Erase all pending reminders from REMINDERS.md. "
+            "Use this after you have acknowledged and acted on the reminders shown in your context."
+        ),
+        parameters=types.Schema(type=types.Type.OBJECT, properties={}),
+    ),
+]