Add an exact-slug Sentry project resolver to the sentry-triage canvas (#2819)

* Fix sentry-triage canvas crash when the `sentry` package isn't bundled

Published awesome-copilot plugins ship extension source only, so the optional
`sentry` npm package the canvas depends on at runtime may be absent. Previously
that made the canvas crash on open instead of guiding the user through setup.

- Load the optional `sentry` package lazily and translate only the top-level
  ERR_MODULE_NOT_FOUND for `sentry` into a package-missing setup state; any other
  import failure (missing transitive dep, entrypoint throwing) is rethrown so a
  real defect isn't masked behind a misleading "reinstall" message.
- Add a dedicated package-missing branch to the connection preflight and a
  matching setup gate, kept distinct from the auth and transient-network gates so
  the user never sees contradictory guidance. The canvas now opens and explains
  what to do rather than crashing.
- Clear `configured` for the package-missing state so the status is no longer the
  contradictory `configured:true` + `setup:'package-missing'`.
- Tell users to sign in with the package-local CLI via `npx sentry auth login`
  run from the extension folder — the only form that resolves after a local
  `npm install`, since a package-local binary isn't on the shell PATH.
- Update the README so the sign-in step and install guidance cover the
  published-plugin layout (`com.github.copilot/extensions/sentry-triage`), not
  just the standalone user/project extension paths.

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

* Add an exact-slug Sentry project resolver to the sentry-triage canvas

The project picker previously only offered projects from the paged list the
canvas had already loaded. Teams with many projects (or a project outside the
first page) had no way to target one by slug. This adds a verify-on-commit
resolver: when a user types a slug that isn't a local match, pressing Enter
checks it against Sentry and only commits the canonical slug once verified,
so a scan never runs against an unverified or wrong-org project.

Canvas / UX (components/page.mjs, styles.mjs):
- Autocomplete accepts an exact slug not in the local list; Enter is the
  explicit commit that triggers resolution (never an as-typed lookup).
- A visually-hidden aria-live region announces checking / verified / not
  found / couldn't-check state, and the resolved state is rendered before
  commit so screen readers hear the outcome.
- Footer/menu surfaces checking, prompt, missing, and error states, including
  when local partial matches are present.
- Project choices are read from an org-keyed cache so a slug from a previously
  selected org can never be treated as local after a free-text org switch;
  the stale-completion guard also compares the org captured for the request.

Server / resolution (server.mjs, sentry.mjs, sentryClient.mjs, extension.mjs):
- CSRF-gated /api/resolve-project verifies a single slug against Sentry.
- Resolution runs on the shared serial request chain and is hardened against
  Sentry outages and queue contention (transient errors are retryable, a
  confirmed miss is cached as "missing").

Also bumps sentry-triage to 1.1.0 (package.json, plugin.json,
marketplace.json).

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

---------

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

extensions/sentry-triage/styles.mjs

@@ -236,6 +236,15 @@ export function styles() {
     .project-ac-item .project-ac-all { color: var(--text-color-muted, #8b949e); font-style: italic; }
     .project-ac-item.active .project-ac-all,
     .project-ac-item:hover .project-ac-all { color: var(--color-fg-on-emphasis, #ffffff); }
+    /* Checkmark on a slug confirmed to exist via a live project.view lookup
+       (a project the paged autocomplete list never reached). */
+    .project-ac-item .project-ac-verified {
+      margin-left: 6px;
+      color: var(--color-success-fg, #3fb950);
+      font-weight: 600;
+    }
+    .project-ac-item.active .project-ac-verified,
+    .project-ac-item:hover .project-ac-verified { color: var(--color-fg-on-emphasis, #ffffff); }
     .project-ac-empty,
     .project-ac-more {
       padding: 6px 8px;