Feat: Add knowledge compilation workflows (#16515)

## Summary
- Add knowledge compilation template APIs, services, and builtin
template seed data
- Add advanced knowledge compile structure/artifact/RAPTOR workflow
support
- Update parsing, dataset/document APIs, and supporting services for
compilation workflows

api/apps/restful_apis/compilation_template_api.py

@@ -0,0 +1,54 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+from quart import Response
+
+from api.apps import current_user, login_required
+from api.apps.restful_apis.utils.compilation_template_validation import validate_template_payload
+from api.db.services.compilation_template_service import CompilationTemplateService
+from api.utils.api_utils import get_json_result, server_error_response
+
+
+_validate_template_payload = validate_template_payload
+
+
+@manager.route("/compilation_templates/builtins", methods=["GET"])  # noqa: F821
+@login_required
+def list_builtin_templates() -> Response:
+    """Built-in template palette — used as the per-child pre-fill in the
+    "Add template group" panel. Groups themselves are always user-created;
+    no builtin groups exist.
+    """
+    try:
+        templates = CompilationTemplateService.list_builtins()
+        if not templates:
+            CompilationTemplateService.seed_builtins_from_files()
+            templates = CompilationTemplateService.list_builtins()
+        if not templates:
+            templates = [
+                {
+                    "id": template["id"],
+                    "kind": template["kind"],
+                    "display_name": template["name"],
+                    "description": template.get("description", ""),
+                    "config": template["config"],
+                }
+                for template in CompilationTemplateService.load_builtins_from_files()
+            ]
+        templates = CompilationTemplateService.fill_default_llm_for_templates(templates, current_user.id)
+        return get_json_result(data=templates)
+    except Exception as exc:
+        return server_error_response(exc)