ci: label pull requests from their changed paths

.github/labeler.yml

@@ -0,0 +1,46 @@
+area/docs:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "docs/**"
+          - "versioned_docs/**"
+          - "versioned_sidebars/**"
+          - "tutorials/**"
+          - "sidebars.js"
+          - "sidebars-tutorials.js"
+          - "versions.json"
+
+area/ui:
+  - changed-files:
+      - any-glob-to-any-file: "src/**"
+
+area/blog:
+  - changed-files:
+      - any-glob-to-any-file: "blog/**"
+
+area/i18n:
+  - changed-files:
+      - any-glob-to-any-file: "i18n/**"
+
+area/edge-functions:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "netlify/**"
+          - "netlify.toml"
+
+area/ci-infra:
+  - changed-files:
+      - any-glob-to-any-file:
+          - ".github/**"
+          - "scripts/**"
+          - "package.json"
+          - "package-lock.json"
+          - ".markdownlint.json"
+          - ".prettierrc"
+          - ".prettierignore"
+
+area/seo:
+  - changed-files:
+      - any-glob-to-any-file:
+          - "static/robots.txt"
+          - "static/llms.txt"
+          - "docusaurus.config.js"

.github/workflows/pr-labeler.yml

@@ -0,0 +1,22 @@
+name: PR Labeler
+
+# pull_request_target is used so that pull requests opened from forks get
+# labeled too. A pull_request run from a fork has a read-only token and cannot
+# add labels. This workflow never checks out or executes pull request code, it
+# only reads the changed file list, so the elevated token is not exposed to it.
+on:
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  label:
+    name: Label by changed paths
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@bf12e9b00b37c5c0ca2b87b79b2daf7891dbda13 # v7.0.0
+        with:
+          sync-labels: false