feat(auth): migrate JWT storage from localStorage to httpOnly cookies

Eliminates XSS token theft risk by storing session JWTs in an httpOnly
cookie (trek_session) instead of localStorage, making them inaccessible
to JavaScript entirely.

- Add cookie-parser middleware and setAuthCookie/clearAuthCookie helpers
- Set trek_session cookie on login, register, demo-login, MFA verify, OIDC exchange
- Auth middleware reads cookie first, falls back to Authorization: Bearer (MCP unchanged)
- Add POST /api/auth/logout to clear the cookie server-side
- Remove all localStorage auth_token reads/writes from client
- Axios uses withCredentials; raw fetch calls use credentials: include
- WebSocket ws-token exchange uses credentials: include (no JWT param)
- authStore initialises isLoading: true so ProtectedRoute waits for /api/auth/me

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

server/package-lock.json

@@ -12,6 +12,7 @@
         "archiver": "^6.0.1",
         "bcryptjs": "^2.4.3",
         "better-sqlite3": "^12.8.0",
+        "cookie-parser": "^1.4.7",
         "cors": "^2.8.5",
         "dotenv": "^16.4.1",
         "express": "^4.18.3",
@@ -34,6 +35,7 @@
         "@types/archiver": "^7.0.0",
         "@types/bcryptjs": "^2.4.6",
         "@types/better-sqlite3": "^7.6.13",
+        "@types/cookie-parser": "^1.4.10",
         "@types/cors": "^2.8.19",
         "@types/express": "^4.17.25",
         "@types/jsonwebtoken": "^9.0.10",
@@ -914,6 +916,16 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/cookie-parser": {
+      "version": "1.4.10",
+      "resolved": "https://registry.npmjs.org/@types/cookie-parser/-/cookie-parser-1.4.10.tgz",
+      "integrity": "sha512-B4xqkqfZ8Wek+rCOeRxsjMS9OgvzebEzzLYw7NHYuvzb7IdxOkI0ZHGgeEBX4PUM7QGVvNSK60T3OvWj3YfBRg==",
+      "dev": true,
+      "license": "MIT",
+      "peerDependencies": {
+        "@types/express": "*"
+      }
+    },
     "node_modules/@types/cors": {
       "version": "2.8.19",
       "resolved": "https://registry.npmjs.org/@types/cors/-/cors-2.8.19.tgz",
@@ -1713,6 +1725,25 @@
         "node": ">= 0.6"
       }
     },
+    "node_modules/cookie-parser": {
+      "version": "1.4.7",
+      "resolved": "https://registry.npmjs.org/cookie-parser/-/cookie-parser-1.4.7.tgz",
+      "integrity": "sha512-nGUvgXnotP3BsjiLX2ypbQnWoGUPIIfHQNZkkC668ntrzGWEZVW70HDEB1qnNGMicPje6EttlIgzo51YSwNQGw==",
+      "license": "MIT",
+      "dependencies": {
+        "cookie": "0.7.2",
+        "cookie-signature": "1.0.6"
+      },
+      "engines": {
+        "node": ">= 0.8.0"
+      }
+    },
+    "node_modules/cookie-parser/node_modules/cookie-signature": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/cookie-signature/-/cookie-signature-1.0.6.tgz",
+      "integrity": "sha512-QADzlaHc8icV8I7vbaJXJwod9HWYp8uCqf1xa4OfNu1T7JVxQIrUgOWtHdNDtPiywmFbiS12VjotIXLrKM3orQ==",
+      "license": "MIT"
+    },
     "node_modules/cookie-signature": {
       "version": "1.0.7",
       "resolved": "https://registry.npmjs.org/cookie-signature/-/cookie-signature-1.0.7.tgz",