feat: apikey alias/renewal + markdown/patch authorship

- APIKey.alias (unique, required). Creating with an existing alias
  renews that key: same key string kept, validity reset to 15d,
  reactivated, name/roles updated (response has renewed=true).
- get_actor(): X-API-Key -> key alias, Bearer -> 'admin'.
- markdown & patch create/update record author / created_at /
  updated_at / last_modified_by from the actor.
- Idempotent run_migrations() (information_schema-guarded ALTERs +
  backfill) so existing tables/data gain the new columns on startup;
  create_all still covers fresh DBs.

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

api/apikey/__init__.py

@@ -1,3 +1,4 @@
+from datetime import datetime, timedelta, UTC
 from flask import Blueprint, request, jsonify
 from api import generate_api_key
 from db import get_db
@@ -10,13 +11,31 @@ api_key_bp = Blueprint('apikey', __name__, url_prefix='/api/apikey')
 # product defines, regardless of what the request body asks for.
 ALLOWED_API_KEY_ROLES = {'admin', 'creator', 'user'}
 
+# Validity window applied on create and on every renewal.
+KEY_TTL = timedelta(days=15)
+
 @api_key_bp.route('/', methods=['POST'])
 @require_auth(roles=['admin'])
 def create_key():
-    data = request.get_json(silent=True)
+    """Create an API key, or renew an existing one.
 
-    if not data or 'name' not in data:
+    `alias` is required and unique. Creating with an alias that already
+    exists is treated as a RENEWAL of that key: the same key string is
+    kept (so existing integrations keep working), its validity window is
+    reset, it is reactivated, and name/roles are updated. The (unchanged)
+    key string is returned again.
+    """
+    data = request.get_json(silent=True)
+    if not data:
+        return jsonify({"error": "invalid or missing JSON body"}), 400
+
+    alias = data.get('alias')
+    name = data.get('name')
+    if not alias or not str(alias).strip():
+        return jsonify({"error": "alias is required"}), 400
+    if not name:
         return jsonify({"error": "Name is required"}), 400
+    alias = str(alias).strip()
 
     roles = data.get('roles', [])
     if not isinstance(roles, list) or any(r not in ALLOWED_API_KEY_ROLES for r in roles):
@@ -24,10 +43,29 @@ def create_key():
 
     try:
         with get_db() as session:
-            apikey = APIKey(key=generate_api_key(), name=data['name'], roles=roles)
+            existing = session.query(APIKey).filter_by(alias=alias).first()
+            if existing is not None:
+                # Renewal: keep the key string, reset validity, reactivate.
+                existing.name = name
+                existing.roles = roles
+                existing.is_active = True
+                existing.expire = datetime.now(UTC) + KEY_TTL
+                session.commit()
+                result = existing.to_dict()
+                result['renewed'] = True
+                return jsonify(result), 200
+
+            apikey = APIKey(
+                key=generate_api_key(),
+                alias=alias,
+                name=name,
+                roles=roles,
+                expire=datetime.now(UTC) + KEY_TTL,
+            )
             session.add(apikey)
             session.commit()
             result = apikey.to_dict()
+            result['renewed'] = False
         return jsonify(result), 201
     except Exception as e:
         return jsonify({"error": str(e)}), 500