Workflow: sparse partial checkout (code and _incoming only), book lookup before processing, safe rebase retry; revert cancel-in-progress

.gitea/workflows/audiobook.yml

@@ -22,7 +22,7 @@ permissions:
 
 concurrency:
   group: audiobook
-  cancel-in-progress: true            # TEMPORARY: clearing a hung run (reverted right after)
+  cancel-in-progress: false           # one book at a time; a second drop waits
 
 jobs:
   build:
@@ -42,7 +42,13 @@ jobs:
         timeout-minutes: 15           # a stalled fetch fails the run instead of hanging it for hours
         uses: actions/checkout@v4
         with:
-          fetch-depth: 0
+          fetch-depth: 100                # enough history to rebase onto a main that moved during a long render
+          filter: blob:none               # do not download every book's audio and PDFs on every run
+          sparse-checkout: |
+            /_pipeline/
+            /_incoming/
+            /.gitea/
+          sparse-checkout-cone-mode: false
       - name: Install tools (fresh container every run)
         run: bash _pipeline/ci/install.sh
       - name: Unit tests (dry runs only)