chore: import upstream snapshot with attribution

.github/workflows/skill-parity.yml

@@ -0,0 +1,41 @@
+name: Skill parity
+
+# Root SKILL.md is the file the public URL serves
+# (https://d.officecli.ai/SKILL.md, raw GitHub URL) and is what
+# `curl ... | bash` consumers fetch. skills/officecli/SKILL.md is a
+# symlink to it — the spec-conforming location that `gh skill install`
+# and `npx skills add` discover, and what the binary embeds.
+#
+# On macOS / Linux the symlink resolves transparently and this diff
+# always passes. The check exists for the Windows case: git on Windows
+# without core.symlinks=true checks out symlinks as plain text files
+# containing the link target path (e.g. literal "../../SKILL.md"), so
+# diff catches that corruption before it ships in a release build.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    paths:
+      - 'SKILL.md'
+      - 'skills/officecli/SKILL.md'
+      - '.github/workflows/skill-parity.yml'
+
+permissions:
+  contents: read
+
+jobs:
+  diff:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - name: Diff root SKILL.md vs skills/officecli/SKILL.md
+        run: |
+          if ! diff -q SKILL.md skills/officecli/SKILL.md; then
+            echo "::error::SKILL.md and skills/officecli/SKILL.md are out of sync."
+            echo "The two files must be byte-identical. The binary embeds skills/officecli/SKILL.md;"
+            echo "the public URL (d.officecli.ai/SKILL.md, raw GitHub) serves the root copy."
+            echo "Fix: cp SKILL.md skills/officecli/SKILL.md (or the reverse) and commit."
+            exit 1
+          fi
+          echo "OK: SKILL.md == skills/officecli/SKILL.md"