fix: restore environment polling after #7284 regression

[talissoncosta]

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• I have filled in the "Changes" section below.
• I have filled in the "How did you test this code" section below.

Changes

Follow-up to #7284.

Bug

Environments that come back with is_creating: true from the API got stuck on the "Preparing your environment" loader indefinitely. A full page reload was the only way to recover.

Root cause

EnvironmentReadyChecker.tsx passed pollingInterval: data?.is_creating ? POLL_INTERVAL_MS : 0 to useGetEnvironmentQuery, where data is the same hook's destructured result. At the time the options object is evaluated, data is unassigned, so the reference silently resolved to undefined and pollingInterval was always 0. Polling never started.

For envs returning is_creating: false on the first fetch (the common case), the component rendered children immediately and the bug was invisible. For envs still in the creating state on the backend, polling never re-fetched, so the UI never detected the transition to ready.

Fix

Gate pollingInterval on a pollingStopped state flag updated by a useEffect after the hook returns. The flag resets when the URL environment changes so polling restarts for newly-visited envs, and flips to true once the env is known-ready or known-bad (error / different project).

How did you test this code?

Manual:

1. Ran the app locally against staging.
2. Temporarily patched the component to force data = { ...rawData, is_creating: true } in the render path so the "Preparing your environment" loader was always displayed.
3. Opened DevTools Network tab, filtered to environments/, navigated to an environment's Features page, and left it for ~1 minute.
4. Before fix: captured HAR showed a single request to /api/v1/environments/{key}/ followed by ~100 seconds of silence — no polling.
5. After fix: a new request to /api/v1/environments/{key}/ fires every ~1 second while is_creating: true. Polling stops cleanly once the response shows is_creating: false, on error, or if the env belongs to a different project. Switching to a different environment resets the flag and restarts polling.

No new unit tests: the frontend's Jest config is Node-only (no jsdom) and there is no existing React component test infrastructure. Worth following up with a dedicated component-test harness PR to guard against this class of regression in the future.

🤖 Generated with Claude Code

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