ci: add docs-sync workflow to open PRs against dojoengine/book

Ports the docs-sync workflow from cartridge-gg/controller to this repo.
On each merged PR to main (and on manual workflow_dispatch), Claude analyzes
the diff and, if user-facing behavior changed, opens an auto-merging PR to
dojoengine/book with targeted docs updates.

Canonical docs location: docs/pages/toolchain/katana/

Requires repository secrets: CREATE_PR_TOKEN, ANTHROPIC_API_KEY.

Author: kronosapiens

.github/workflows/docs-sync.yml

@@ -0,0 +1,33 @@
+name: doc-sync
+
+on:
+  pull_request:
+    types: [closed]
+    branches: [main]
+  workflow_dispatch:
+    inputs:
+      commit_sha:
+        description: "Commit SHA to analyze for documentation updates"
+        required: true
+        type: string
+
+jobs:
+  docs-sync:
+    if: github.event.pull_request.merged == true || github.event_name == 'workflow_dispatch'
+    uses: dojoengine/book/.github/workflows/docs-sync.yml@main
+    with:
+      target-docs-repo: dojoengine/book
+      source-repo-name: katana
+      source-repo-slug: dojoengine/katana
+      diff-globs: |
+        *.rs
+        *.toml
+        *.md
+      docs-patterns: |
+        ^crates/.*\.rs$
+        ^bin/.*\.rs$
+      canonical-desc: |
+        Katana is documented at docs-repo/docs/pages/toolchain/katana/ — this is the single canonical location for katana docs.
+      docs-structure-desc: |
+        The site uses Vocs. Content lives in `docs-repo/docs/pages/`. Navigation is in `docs-repo/routes.ts`. SDK docs at `docs-repo/docs/pages/client/sdk/` are single `.md` files (bevy.md, javascript.md, unity.md, unrealengine.md, godot.md, rust.md, telegram.md), not subdirectories — the sole exception is `c/` which is a subdir.
+    secrets: inherit