ci(pr-validation): validate PR title + body against the template

New .github/workflows/pr-validation.yml (pull_request_target, like seerr, so it
works on fork PRs without checking out fork code): moves the Conventional-Commits
title check out of the quality gate and adds a PR template check
(scripts/check-pr-template.mjs) — Description/Ticket/Testing filled, contribution
+ AI-disclosure boxes ticked (maintainers bypass AI), and Screenshots required
when the PR changes UI (.tsx under app/ or components/). Posts a sticky comment +
'blocked: template' label on failure, clears on success; skips bots + synchronize.
Robust comment stripping (CodeQL-safe). Inspired by seerr's pr-validation.

.github/workflows/linting.yml

@@ -12,38 +12,6 @@ permissions:
   contents: read
 
 jobs:
-  validate_pr_title:
-    name: "📝 Validate PR Title"
-    if: github.event_name == 'pull_request'
-    runs-on: ubuntu-24.04
-    permissions:
-      pull-requests: write
-      contents: read
-    steps:
-      - uses: amannn/action-semantic-pull-request@48f256284bd46cdaab1048c3721360e808335d50 # v6.1.1
-        id: lint_pr_title
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - uses: marocchino/sticky-pull-request-comment@0ea0beb66eb9baf113663a64ec522f60e49231c0 # v3.0.4
-        if: always() && (steps.lint_pr_title.outputs.error_message != null)
-        with:
-          header: pr-title-lint-error
-          message: |
-            Hey there and thank you for opening this pull request! 👋🏼
-            We require pull request titles to follow the [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/).
-
-            **Error details:**
-            ```
-            ${{ steps.lint_pr_title.outputs.error_message }}
-            ```
-
-      - if: ${{ steps.lint_pr_title.outputs.error_message == null }}
-        uses: marocchino/sticky-pull-request-comment@0ea0beb66eb9baf113663a64ec522f60e49231c0 # v3.0.4
-        with:
-          header: pr-title-lint-error
-          delete: true
-
   dependency-review:
     name: 🔍 Vulnerable Dependencies
     runs-on: ubuntu-24.04