feat: merge langbot-docs history into docs/ (subtree, no squash)

Imported langbot-app/langbot-docs main (51dddcb3f) under docs/ with
`git subtree add`, keeping every original commit SHA and signature so the
mirror and landing-page submodule can fast-forward from a `git subtree
split` later. Retarget the docs workflows to docs/, point blog sync at the
main repository, and update the remaining internal references.

Co-Authored-By: Mika (Multica) <[email protected]>
Co-authored-by: multica-agent <[email protected]>

docs/.github/workflows/sync-github-wiki.yml

@@ -1,87 +1,13 @@
-name: Sync GitHub Wiki
-
+# Workflows run from langbot-app/LangBot/.github/workflows after migration.
+# Keep this mirror entry inert: no job may write directly to langbot-docs.
+name: Legacy docs workflow (migrated)
 on:
-  push:
-    branches: [main]
-    paths:
-      - "en/**"
-      - "zh/**"
-      - "ja/**"
-      - "scripts/build-github-wiki.py"
-      - ".github/workflows/sync-github-wiki.yml"
-  pull_request:
-    paths:
-      - "en/**"
-      - "zh/**"
-      - "ja/**"
-      - "scripts/build-github-wiki.py"
-      - "tests/test_build_github_wiki.py"
-      - ".github/workflows/sync-github-wiki.yml"
   workflow_dispatch:
-
 permissions:
   contents: read
-
-concurrency:
-  group: sync-langbot-github-wiki
-  cancel-in-progress: false
-
 jobs:
-  build:
-    name: Build Wiki mirror
+  migrated:
+    if: ${{ false }}
     runs-on: ubuntu-latest
-    timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v7
-      - uses: actions/setup-python@v7
-        with:
-          python-version: "3.12"
-      - name: Run converter tests
-        run: python -m unittest tests/test_build_github_wiki.py
-      - name: Build Wiki pages
-        run: python scripts/build-github-wiki.py --output dist/github-wiki
-      - name: Validate generated pages
-        run: |
-          test -f dist/github-wiki/Home.md
-          test -f dist/github-wiki/_Sidebar.md
-          test "$(find dist/github-wiki -maxdepth 1 -name '*.md' | wc -l)" -gt 250
-      - name: Upload generated Wiki
-        uses: actions/upload-artifact@v7
-        with:
-          name: github-wiki
-          path: dist/github-wiki
-          if-no-files-found: error
-
-  sync:
-    name: Publish to LangBot Wiki
-    if: github.event_name != 'pull_request'
-    needs: build
-    runs-on: ubuntu-latest
-    timeout-minutes: 5
-    steps:
-      - uses: actions/download-artifact@v8
-        with:
-          name: github-wiki
-          path: generated
-      - name: Clone target Wiki
-        env:
-          WIKI_PUSH_TOKEN: ${{ secrets.LANGBOT_WIKI_PUSH_TOKEN }}
-        run: |
-          test -n "$WIKI_PUSH_TOKEN"
-          git clone "https://x-access-token:${WIKI_PUSH_TOKEN}@github.com/langbot-app/LangBot.wiki.git" target
-      - name: Replace and publish Wiki contents
-        env:
-          SOURCE_SHA: ${{ github.sha }}
-        run: |
-          find target -mindepth 1 -maxdepth 1 ! -name .git -exec rm -rf {} +
-          cp -a generated/. target/
-          cd target
-          git add -A
-          if git diff --cached --quiet; then
-            echo "GitHub Wiki is already up to date."
-            exit 0
-          fi
-          git config user.name "langbot-docs-sync[bot]"
-          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
-          git commit -m "docs: sync from langbot-docs@${SOURCE_SHA::7}"
-          git push origin HEAD:master
+      - run: echo 'Use the LangBot repository workflows.'