ci: path-based skip and gate job in pr_checks (#3615)

`pr_checks` runs the full matrix on every PR. #3609 touched only
`apps/webapp/app/routes/admin.tsx` and still ran the 4-job CLI e2e
matrix and 5-job sdk-compat suite.

Adds a `changes` job using `dorny/paths-filter` and gates each tier:

- webapp + e2e-webapp: `apps/webapp/**`, `packages/**`,
`internal-packages/**`
- packages: `packages/**`
- internal: `internal-packages/**` + `packages/**` (cross-deps)
- e2e (cli-v3): `packages/{cli-v3,build,core,schema-to-json}/**`
- sdk-compat: `packages/{trigger-sdk,core}/**`

`.configs/**`, `package.json`, `pnpm-lock.yaml`, `pnpm-workspace.yaml`,
`turbo.json` are also included in every filter since they affect the
whole workspace.

Inlines the `units` reusable-workflow children so each can be gated
independently (status check names also flatten from `units / webapp /
...` to `webapp / ...`). `unit-tests.yml` is unaffected - still used by
`publish.yml`.

Adds an `all-checks` gate that always runs and short-circuits to success
when every dependent is success-or-skipped. With this in place a single
required status check (`All PR Checks`) is enough; before this,
`paths-ignore` would have left required checks Pending on docs/changeset
PRs ([gh
docs](https://docs.github.com/en/actions/managing-workflow-runs/skipping-workflow-runs)).

.github/workflows/pr_checks.yml

@@ -3,11 +3,6 @@ name: 🤖 PR Checks
 on:
   pull_request:
     types: [opened, synchronize, reopened]
-    paths-ignore:
-      - "docs/**"
-      - ".changeset/**"
-      - "hosting/**"
-      - ".github/workflows/helm-prerelease.yml"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
@@ -15,21 +10,155 @@ concurrency:
 
 permissions:
   contents: read
+  pull-requests: read
 
 jobs:
+  changes:
+    name: Detect changes
+    runs-on: ubuntu-latest
+    outputs:
+      code: ${{ steps.filter.outputs.code }}
+      webapp: ${{ steps.filter.outputs.webapp }}
+      packages: ${{ steps.filter.outputs.packages }}
+      internal: ${{ steps.filter.outputs.internal }}
+      cli: ${{ steps.filter.outputs.cli }}
+      sdk: ${{ steps.filter.outputs.sdk }}
+    steps:
+      - uses: dorny/paths-filter@fbd0ab8f3e69293af611ebaee6363fc25e6d187d # v4.0.1
+        id: filter
+        with:
+          filters: |
+            code:
+              - '**'
+              - '!docs/**'
+              - '!.changeset/**'
+              - '!hosting/**'
+              - '!.github/workflows/helm-prerelease.yml'
+            webapp:
+              - 'apps/webapp/**'
+              - 'packages/**'
+              - 'internal-packages/**'
+              - '.github/workflows/pr_checks.yml'
+              - '.github/workflows/unit-tests-webapp.yml'
+              - '.github/workflows/e2e-webapp.yml'
+              - '.configs/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'turbo.json'
+            packages:
+              - 'packages/**'
+              - '.github/workflows/pr_checks.yml'
+              - '.github/workflows/unit-tests-packages.yml'
+              - '.configs/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'turbo.json'
+            internal:
+              - 'internal-packages/**'
+              - 'packages/**'
+              - '.github/workflows/pr_checks.yml'
+              - '.github/workflows/unit-tests-internal.yml'
+              - '.configs/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'turbo.json'
+            cli:
+              - 'packages/cli-v3/**'
+              - 'packages/build/**'
+              - 'packages/core/**'
+              - 'packages/schema-to-json/**'
+              - '.github/workflows/pr_checks.yml'
+              - '.github/workflows/e2e.yml'
+              - '.configs/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'turbo.json'
+            sdk:
+              - 'packages/trigger-sdk/**'
+              - 'packages/core/**'
+              - '.github/workflows/pr_checks.yml'
+              - '.github/workflows/sdk-compat.yml'
+              - '.configs/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'turbo.json'
+
   typecheck:
+    needs: changes
+    if: needs.changes.outputs.code == 'true'
     uses: ./.github/workflows/typecheck.yml
 
-  units:
-    uses: ./.github/workflows/unit-tests.yml
+  webapp:
+    needs: changes
+    if: needs.changes.outputs.webapp == 'true'
+    uses: ./.github/workflows/unit-tests-webapp.yml
+    secrets:
+      DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
+      DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
+
+  e2e-webapp:
+    needs: changes
+    if: needs.changes.outputs.webapp == 'true'
+    uses: ./.github/workflows/e2e-webapp.yml
+    secrets:
+      DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
+      DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
+
+  packages:
+    needs: changes
+    if: needs.changes.outputs.packages == 'true'
+    uses: ./.github/workflows/unit-tests-packages.yml
+    secrets:
+      DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
+      DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
+
+  internal:
+    needs: changes
+    if: needs.changes.outputs.internal == 'true'
+    uses: ./.github/workflows/unit-tests-internal.yml
     secrets:
       DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
       DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
 
   e2e:
+    needs: changes
+    if: needs.changes.outputs.cli == 'true'
     uses: ./.github/workflows/e2e.yml
     with:
       package: cli-v3
 
   sdk-compat:
+    needs: changes
+    if: needs.changes.outputs.sdk == 'true'
     uses: ./.github/workflows/sdk-compat.yml
+
+  all-checks:
+    name: All PR Checks
+    needs:
+      - changes
+      - typecheck
+      - webapp
+      - e2e-webapp
+      - packages
+      - internal
+      - e2e
+      - sdk-compat
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      - name: Verify all checks
+        run: |
+          if [[ "${{ contains(needs.*.result, 'failure') }}" == "true" ]]; then
+            echo "One or more checks failed"
+            exit 1
+          fi
+          if [[ "${{ contains(needs.*.result, 'cancelled') }}" == "true" ]]; then
+            echo "One or more checks were cancelled"
+            exit 1
+          fi
+          echo "All checks passed or were skipped due to path filters"