ci(forgejo): bump gpx test timeout (heavy fit-parser cold import)

Same runner cold-import slowness as @trails-cool/db: the gpx→fit round-trip
test's import exceeds vitest's 5s default under CI CPU contention.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/gpx/package.json

@@ -8,7 +8,7 @@
   "main": "./src/index.ts",
   "types": "./src/index.ts",
   "scripts": {
-    "test": "vitest run",
+    "test": "vitest run --testTimeout=20000",
     "lint": "eslint .",
     "typecheck": "tsc"
   },