chore: pin all dependency versions for reproducible builds

Remove ^ prefix from all 33 dependencies across root, server, and
frontend package.json files. Lockfile regenerated and verified with
pnpm install --frozen-lockfile.

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

package.json

@@ -14,13 +14,13 @@
     "test:e2e": "playwright test --config e2e/playwright.config.ts"
   },
   "devDependencies": {
-    "@playwright/test": "^1.58.2",
-    "@typescript-eslint/eslint-plugin": "^8.56.1",
-    "@typescript-eslint/parser": "^8.56.1",
-    "concurrently": "^9.1.2",
-    "eslint": "^10.0.3",
-    "eslint-plugin-security": "^4.0.0",
-    "typescript": "^5.7.3",
-    "vitest": "^3.1.1"
+    "@playwright/test": "1.58.2",
+    "@typescript-eslint/eslint-plugin": "8.56.1",
+    "@typescript-eslint/parser": "8.56.1",
+    "concurrently": "9.1.2",
+    "eslint": "10.0.3",
+    "eslint-plugin-security": "4.0.0",
+    "typescript": "5.7.3",
+    "vitest": "3.1.1"
   }
 }