Add docs/ as wiki source of truth with auto-sync workflow

.github/workflows/wiki-sync.yml

@@ -0,0 +1,26 @@
+name: Sync docs to wiki
+
+# The wiki is a generated mirror of docs/. Edit docs/ via pull requests;
+# this publishes them to the GitHub wiki on every merge to main.
+on:
+  push:
+    branches: [main]
+    paths: ['docs/**']
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+concurrency:
+  group: wiki-sync
+  cancel-in-progress: true
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Publish docs/ to wiki
+        uses: Andrew-Chen-Wang/github-wiki-action@50650fccf3a10f741995523cf9708c53cec8912a # v4
+        with:
+          path: docs/