feat: migrate Inner API module to Flask-RESTX (#24492)

api/controllers/inner_api/__init__.py

@@ -1,10 +1,23 @@
 from flask import Blueprint
+from flask_restx import Namespace
 
 from libs.external_api import ExternalApi
 
 bp = Blueprint("inner_api", __name__, url_prefix="/inner/api")
-api = ExternalApi(bp)
+
+api = ExternalApi(
+    bp,
+    version="1.0",
+    title="Inner API",
+    description="Internal APIs for enterprise features, billing, and plugin communication",
+    doc="/docs",  # Enable Swagger UI at /inner/api/docs
+)
+
+# Create namespace
+inner_api_ns = Namespace("inner_api", description="Internal API operations", path="/")
 
 from . import mail
 from .plugin import plugin
 from .workspace import workspace
+
+api.add_namespace(inner_api_ns)