fix(ci): use full clone to prevent history loss on amend + force push

actions/checkout@v4 defaults to depth=1. When the CI amends the
triggering commit and force-pushes, the shallow history replaces
the full history on the remote — wiping all prior commits.

Fix: set fetch-depth: 0 for full clone.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/build-openclaw.yml

@@ -21,6 +21,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - uses: actions/setup-python@v5
         with: