Add kreuzberg MCP shared workflow (#28392)

Author: Copilot

.github/workflows/shared/mcp/kreuzberg.md

@@ -0,0 +1,88 @@
+---
+mcp-servers:
+  kreuzberg:
+    container: "ghcr.io/kreuzberg-dev/kreuzberg"
+    version: "latest"
+    entrypointArgs:
+      - "mcp"
+    mounts:
+      - ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE}:ro
+    allowed:
+      # Document extraction tools (read-only)
+      - "extract_file"
+      - "extract_bytes"
+      - "batch_extract_files"
+      # Format discovery tools (read-only)
+      - "detect_mime_type"
+      - "list_formats"
+      - "get_version"
+      # Text processing tools (read-only)
+      - "embed_text"
+      - "chunk_text"
+      # Cache inspection tools (read-only)
+      - "cache_stats"
+      - "cache_manifest"
+      # Excluded write/mutating operations:
+      # - "cache_clear"   # Evicts all cached results
+      # - "cache_warm"    # Pre-downloads embedding models
+      # Excluded feature-flag-gated operations:
+      # - "extract_structured"  # Requires liter-llm feature flag at build time
+---
+<!--
+## Kreuzberg MCP Server
+
+Kreuzberg is a polyglot document intelligence engine. The MCP server exposes its
+full extraction engine as 13 discoverable tools, communicating over stdin/stdout
+with JSON-RPC 2.0. It supports 97+ file formats including PDF, DOCX, PPTX,
+images (with Tesseract OCR), and legacy Office formats (with LibreOffice in the
+full image).
+
+Documentation: https://docs.kreuzberg.dev/guides/docker/
+MCP integration guide: https://docs.kreuzberg.dev/guides/mcp-integration/
+GitHub: https://github.com/kreuzberg-dev/kreuzberg
+
+### Container images
+
+Two images are available (both on `ghcr.io/kreuzberg-dev/kreuzberg`):
+- **Core** (~1.0–1.3 GB): Modern formats, Tesseract OCR (12 languages)
+- **Full** (~1.5–2.1 GB): Adds LibreOffice for legacy `.doc`/`.ppt` files
+  Use tag `full` or `latest-full` to select the full image.
+
+### Required secrets
+
+None — no API token is required.
+
+### Available tools (read-only)
+
+| Tool | Params | Description |
+|---|---|---|
+| `extract_file` | `path` | Extract text and metadata from a local file |
+| `extract_bytes` | `data` (base64) | Extract from base64-encoded file content |
+| `batch_extract_files` | `paths` | Extract multiple files in one call |
+| `detect_mime_type` | `path` | Identify a file's MIME type |
+| `list_formats` | — | List all supported file formats |
+| `get_version` | — | Return the library version string |
+| `embed_text` | `texts` | Generate embedding vectors for text chunks |
+| `chunk_text` | `text` | Split text into overlapping chunks |
+| `cache_stats` | — | Report how much content is cached |
+| `cache_manifest` | — | Return model checksums |
+
+### Excluded tools
+
+- `cache_clear` — Evicts all cached results (write operation)
+- `cache_warm` — Pre-downloads embedding models (write operation)
+- `extract_structured` — Requires the `liter-llm` build-time feature flag
+
+### Workspace access
+
+The workspace is mounted read-only at the same path it exists on the host,
+so `extract_file` and `batch_extract_files` can reference files using their
+absolute workspace paths (e.g. `${{ github.workspace }}/document.pdf`).
+
+### Usage in workflows
+
+```yaml
+imports:
+  - shared/mcp/kreuzberg.md
+```
+-->