Expand staging test suite: full status-transition coverage

[darreneid]

Builds on the staging suite (#2, now merged) with much broader coverage.

Added

• api_update transition matrix — all 12 ordered status pairs among new/open/snoozed/closed, each asserting the recorded row (from/to, source=api_update, acting user_id, null post_id, non-negative duration).
• Full post_created branches:
  • Customer reply reopening snoozed → open; closed → open (recent + last-assigned, reassigned), → new (no last-assignee), → new (closed > 1 month ago).
  • Customer reply to new/open → sets waiting_*, no row.
  • Admin whisper reopening snoozed → open; closed → open/new; open → no change/no row (skips if whispers disabled).
  • Admin regular reply → clears waiting_*, no row.
• Edge cases: invalid status → 422; no-op status → no row; row attributed to the pre-change assignee.

27 checks total (the matrix expands from one loop).

Rate limits

api() now honors 429s (waits the server-provided wait_seconds, bounded) so a full run (~30 topics) completes even on rate-limited instances.

Testing

Validated against a local Discourse dev instance with Data Explorer (real HTTP + real TopicStatusChange rows): 27/27 pass, including the auto-wait path, with cleanup.

🤖 Generated with Claude Code

[darreneid]

Superseded by #4 — the exhaustive status-transition coverage now lives as CI-gated rspec (no staging/API-key/DB limits, and it covers the no-status case the API suite couldn't reach). The thin API smoke suite from #2 remains in staging for post-deploy checks.