fix(hetznercloud): poll zone action endpoint instead of server action

[legend813]

What

waitAction for the hetznercloud provider polls the server action endpoint for what is a zone action:

url := fmt.Sprintf("https://api.hetzner.cloud/v1/servers/actions/%d", id)

Record writes (add_rrset_records, set_rrset_records, …) return an action that lives under /v1/zones/actions/{id}. Looking it up under /v1/servers/actions/{id} returns 404 not_found, which handleErrorResponse turns into an update failure — even though the record write itself succeeded.

Why it matters

The DNS record is written correctly, but the update is recorded as failed. Consequences reported in #1136:

• updates.json is never updated, so the Web UI shows a stale "Current IP" indefinitely
• the healthcheck compares against that stale state, so the container stays unhealthy
• reverse proxies that filter on container health drop the Web UI

Reproduction

Against a live Hetzner Cloud DNS zone, using the same action ID returned by a record write:

$ curl -H "Authorization: Bearer $TOKEN" https://api.hetzner.cloud/v1/zones/actions
{"actions":[{"id":<action-id>,"command":"add_rrset_records","status":"success", ...

$ curl -o /dev/null -w '%{http_code}\n' -H "Authorization: Bearer $TOKEN" \
    https://api.hetzner.cloud/v1/zones/actions/<action-id>
200

$ curl -o /dev/null -w '%{http_code}\n' -H "Authorization: Bearer $TOKEN" \
    https://api.hetzner.cloud/v1/servers/actions/<action-id>
404

Same ID, both endpoints — only the zone one resolves. On accounts with no cloud servers, /v1/servers/actions is empty, so every lookup necessarily 404s.

Change

One-line fix plus a regression test that asserts the polled path and covers the error action status.

Verified on v2.10.0 (commit 6499618) against a real zone: with the fix, record updates are recorded as successful.

Fixes #1136

[qdm12]

Isn't this the same as now-merged #1166 ?

[buddhaCode]

Yes, same change as #1166. The diff is identical, and master already carries it since that merge, so there is nothing left for this PR to apply.