feat(pr-lint): consolidate dependency review into pr-lint action (#497)

* feat(pr-lint): consolidate dependency review into pr-lint action

Move dependency review from standalone workflow into the pr-lint
composite action. Adds repository visibility check via GitHub API
and runs dependency-review-action only on public repos during
pull_request events, before MegaLinter.

* fix(pr-lint): harden dependency review visibility check

Address PR review feedback from Copilot and CodeRabbit:
- Skip visibility check on non-PR events (if: pull_request)
- Add continue-on-error so API failures don't block MegaLinter
- Use curl --fail --show-error to surface HTTP errors in logs
- Use github.token directly instead of inputs.token fallback
- Add Accept header for GitHub API versioning
- Validate jq output type to fail closed on bad API responses

* fix(pr-lint): use event payload for visibility, unblock MegaLinter on dep review

Replace curl API call with local jq read from $GITHUB_EVENT_PATH for
the repository visibility check — simpler, faster, no auth needed.

Add continue-on-error to dependency review so MegaLinter always runs,
with a re-fail step after artifacts upload to preserve the failure signal.

.github/workflows/dependency-review.yml

@@ -1,18 +0,0 @@
----
-# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
-name: 'Dependency Review'
-on:
-  - pull_request
-
-permissions: {}
-
-jobs:
-  dependency-review:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-    steps:
-      - name: 'Checkout Repository'
-        uses: actions/checkout@71cf2267d89c5cb81562390fa70a37fa40b1305e # v6-beta
-      - name: 'Dependency Review'
-        uses: actions/dependency-review-action@2031cfc080254a8a887f58cffee85186f0e49e48 # v4.9.0