ci: cask do tapu przez GitHub App renacode-tap zamiast PAT

HOMEBREW_TAP_TOKEN był fine-grained PAT-em właściciela, wygasającym
7.10.2027. Teraz job robi godzinny token aplikacji `renacode-tap`
(Contents: write) ograniczony do RenaCode/homebrew-tap
(actions/create-github-app-token v3.2.0, przypięta po SHA).
Sekret TAP_APP_KEY + zmienna TAP_APP_CLIENT_ID.

Token i próba `git ls-remote` tapu chodzą przy KAŻDYM przebiegu, więc
utrata instalacji wychodzi na PR, a nie po opublikowaniu DMG.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: mbeczynski

.github/workflows/release.yml

@@ -27,7 +27,9 @@ name: Release
 #     Without it the release does NOT build: an ad-hoc signature changes the
 #     app's identity on every release and macOS revokes Full Disk Access after
 #     every upgrade.
-#   HOMEBREW_TAP_TOKEN - token with write access to RenaCode/homebrew-tap.
+#   TAP_APP_KEY (secret) + TAP_APP_CLIENT_ID (variable) - GitHub App `renacode-tap`
+#     (Contents: write, installed on RenaCode/homebrew-tap). The job mints a
+#     1-hour token scoped to that one repository; nothing expires.
 #
 # Still no Developer ID and no notarization - Gatekeeper does not know the
 # publisher; the cask removes the quarantine attribute in postflight.
@@ -277,23 +279,41 @@ jobs:
             mac-app/build/*.sha256
           generate_release_notes: true
 
-      - name: Check tap token
+      - name: Check tap app
         if: env.IS_RELEASE == 'true'
         env:
-          TAP_TOKEN: ${{ secrets.HOMEBREW_TAP_TOKEN }}
+          TAP_APP_CLIENT_ID: ${{ vars.TAP_APP_CLIENT_ID }}
+          TAP_APP_KEY: ${{ secrets.TAP_APP_KEY }}
         run: |
-          if [ -z "$TAP_TOKEN" ]; then
-            echo "::error::Release published, but HOMEBREW_TAP_TOKEN is missing - the cask in the tap was NOT updated. Contents to insert manually:"
+          if [ -z "$TAP_APP_CLIENT_ID" ] || [ -z "$TAP_APP_KEY" ]; then
+            echo "::error::Release published, but TAP_APP_CLIENT_ID/TAP_APP_KEY is missing - the cask in the tap was NOT updated. Contents to insert manually:"
             cat mac-app/build/cloudmachine.rb
             exit 1
           fi
 
+      # Token and the access probe run on EVERY build, not only on release:
+      # an app that lost its installation (or a missing key) fails the PR,
+      # not the release after the DMG is already published.
+      - name: Tap token
+        id: tap-token
+        uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1 # v3.2.0
+        with:
+          client-id: ${{ vars.TAP_APP_CLIENT_ID }}
+          private-key: ${{ secrets.TAP_APP_KEY }}
+          owner: RenaCode
+          repositories: homebrew-tap
+
+      - name: Check tap access
+        env:
+          TAP_TOKEN: ${{ steps.tap-token.outputs.token }}
+        run: git ls-remote "https://x-access-token:${TAP_TOKEN}@github.com/RenaCode/homebrew-tap.git" HEAD
+
       - name: Check out tap
         if: env.IS_RELEASE == 'true'
         uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
         with:
           repository: RenaCode/homebrew-tap
-          token: ${{ secrets.HOMEBREW_TAP_TOKEN }}
+          token: ${{ steps.tap-token.outputs.token }}
           path: homebrew-tap
 
       - name: Push cask to tap

packaging/README.md

@@ -80,15 +80,21 @@ rm -rf "$work"
 Do this **once**. A new certificate is a new identity: every Mac would have to
 grant Full Disk Access again.
 
-### 2. The tap repository and `HOMEBREW_TAP_TOKEN`
+### 2. The tap repository and the `renacode-tap` app
 
 1. Create the public repository `RenaCode/homebrew-tap` (empty is fine; the
    workflow creates `Casks/`).
-2. Create a fine-grained token limited to that repository with
-   *Contents: Read and write*, and store it:
-   `gh secret set HOMEBREW_TAP_TOKEN -R RenaCode/CloudMachine`
+2. Create a GitHub App in the RenaCode organization (no webhook, Repository
+   permissions *Contents: Read and write*), install it on `homebrew-tap` only,
+   and store its client ID and private key:
+   `gh variable set TAP_APP_CLIENT_ID -R RenaCode/CloudMachine --body <client id>`
+   `gh secret set TAP_APP_KEY -R RenaCode/CloudMachine < key.pem`
 
-Without the token the release is still published, but the job fails and
+   The release job turns the key into a one-hour token for `homebrew-tap`
+   (`actions/create-github-app-token`), so there is no token to renew. The app
+   is `renacode-tap` (since 2026-10-23; before that a fine-grained PAT).
+
+Without the app the release is still published, but the job fails and
 prints the cask, so a missing tap update cannot go unnoticed.
 
 ## What the cask does and deliberately does not do