ci: harden the qdrant integration job

The integration test job has been failing intermittently on main and on
open pull requests with `httpx.ReadTimeout: timed out` on the first write
to Qdrant, while `GET /collections` and `/healthz` kept answering.

Cause: the qdrant-client default request timeout is 5 seconds, and the job
only waits for `/healthz`, which is served before the storage engine
accepts writes. On a shared runner doing several builds at once, the first
collection creation or indexing exceeds 5s and the whole fixture errors
out.

- pin qdrant/qdrant to v1.19 (the digest `latest` and the cluster already
  run) and let Renovate track the pin in the workflows as well
- wait for a real write round-trip (create + delete a probe collection)
  instead of `/healthz` alone, and dump the container logs if it never
  becomes writable
- make the Qdrant client timeout configurable via QDRANT_TIMEOUT and set
  it to 60s in CI, where there is no latency SLA

renovate.json

@@ -3,9 +3,12 @@
   "customManagers": [
     {
       "customType": "regex",
-      "description": "Track qdrant/qdrant Docker image from docker-compose.yml (native manager missed it)",
-      "managerFilePatterns": ["/^docker-compose\\.ya?ml$/"],
-      "matchStrings": ["image:\\s*(?:docker\\.io/)?qdrant/qdrant:(?<currentValue>[^\\s]+)"],
+      "description": "Track the pinned qdrant/qdrant image in docker-compose.yml and the CI workflows (native manager missed it)",
+      "managerFilePatterns": [
+        "/^docker-compose\\.ya?ml$/",
+        "/^\\.gitea/workflows/.*\\.ya?ml$/"
+      ],
+      "matchStrings": ["(?:docker\\.io/)?qdrant/qdrant:(?<currentValue>[^\\s\"']+)"],
       "depNameTemplate": "qdrant/qdrant",
       "datasourceTemplate": "docker"
     }