feat: refactor sgclaw around zeroclaw compat runtime

third_party/zeroclaw/.github/workflows/README.md

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+# Workflow Directory Layout
+
+GitHub Actions only loads workflow entry files from:
+
+- `.github/workflows/*.yml`
+- `.github/workflows/*.yaml`
+
+Subdirectories are not valid locations for workflow entry files.
+
+Repository convention:
+
+1. Keep runnable workflow entry files at `.github/workflows/` root.
+2. Keep cross-tooling/local CI scripts under `dev/` or `scripts/ci/` when used outside Actions.
+
+Workflow behavior documentation in this directory:
+
+- `.github/workflows/master-branch-flow.md`