Fix sentry-triage bug bash issues and stream org project pagination (#2948)

Bug-bash fixes for the sentry-triage canvas extension:

- Model list: auto-refresh via session.rpc.model.list() with a static
  fallback, instead of a hardcoded list that went stale.
- Plain-English toggle: gate the toggle until enrichPlainEnglish()
  completes, fixing a race where it was interactive before enrichment
  finished. Add a preparing hint while it runs.
- Copy: 'Plain-English titles' -> 'Plain-English messages'; simplify the
  loading hint.
- Work status labels: distinguish 'starting Copilot fix session' vs
  'filing tracking issue' instead of a generic 'working', and mark the
  Fix-with-Copilot toast as non-blocking.
- Org project pagination: page the traversal as discrete queued tasks
  bounded by page count, driven by the SDK envelope hasMore flag, so a
  mega-org no longer starves interactive lookups and an incomplete
  traversal is never cached as complete. No Promise.race timeout is used
  because sentry@0.42.2 exposes no per-call cancellation and an abandoned
  call would corrupt module-global cursor state.

Bump plugin to 1.2.0 and regenerate marketplace.json.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

.github/plugin/marketplace.json

@@ -1515,7 +1515,7 @@
       "name": "sentry-triage",
       "source": "plugins/sentry-triage",
       "description": "Scan live Sentry issues in a Copilot canvas, group them by urgency, and hand issues off for tracking or a fix PR.",
-      "version": "1.1.0"
+      "version": "1.2.0"
     },
     {
       "name": "signals-dashboard",