Merge remote-tracking branch 'origin/master' into feat/sandbox

# Conflicts:
#	src/langbot/pkg/api/http/controller/groups/plugins.py
#	src/langbot/pkg/core/app.py
#	src/langbot/pkg/core/stages/build_app.py
#	src/langbot/templates/config.yaml
#	uv.lock
#	web/src/app/home/components/home-sidebar/HomeSidebar.tsx
#	web/src/app/home/components/home-sidebar/SidebarDataContext.tsx
#	web/src/app/home/layout.tsx
#	web/src/app/home/plugins/components/plugin-market/PluginMarketComponent.tsx
#	web/src/i18n/locales/en-US.ts
#	web/src/i18n/locales/es-ES.ts
#	web/src/i18n/locales/ja-JP.ts
#	web/src/i18n/locales/th-TH.ts
#	web/src/i18n/locales/vi-VN.ts
#	web/src/i18n/locales/zh-Hans.ts
#	web/src/i18n/locales/zh-Hant.ts
#	web/src/router.tsx

src/langbot/pkg/api/http/controller/groups/plugins.py

@@ -7,11 +7,38 @@ import httpx
 import uuid
 import os
 from urllib.parse import urlparse
+import posixpath
 
 from .....core import taskmgr
 from .. import group
 from langbot_plugin.runtime.plugin.mgr import PluginInstallSource
 
+# Resolve the built-in page SDK JS from the langbot_plugin package
+_PAGE_SDK_PATH = None
+try:
+    import langbot_plugin.assets as _assets_pkg
+
+    _candidate = os.path.join(os.path.dirname(_assets_pkg.__file__), 'langbot-page-sdk.js')
+    if os.path.exists(_candidate):
+        _PAGE_SDK_PATH = _candidate
+except Exception:
+    pass
+
+
+def _normalize_plugin_asset_path(filepath: str) -> str | None:
+    filepath = filepath.replace('\\', '/')
+    if filepath.startswith('/'):
+        return None
+
+    normalized = posixpath.normpath(filepath)
+    if normalized == '.' or normalized.startswith('../') or normalized == '..':
+        return None
+
+    if normalized.startswith('components/pages/'):
+        return normalized
+
+    return f'assets/{normalized}'
+
 
 @group.group_class('plugins', '/api/v1/plugins')
 class PluginsRouterGroup(group.RouterGroup):
@@ -65,6 +92,15 @@ class PluginsRouterGroup(group.RouterGroup):
         return None
 
     async def initialize(self) -> None:
+        @self.route('/_sdk/page-sdk.js', methods=['GET'], auth_type=group.AuthType.NONE)
+        async def _() -> quart.Response:
+            """Serve the built-in LangBot page SDK JavaScript."""
+            if _PAGE_SDK_PATH and os.path.exists(_PAGE_SDK_PATH):
+                with open(_PAGE_SDK_PATH, 'r') as f:
+                    content = f.read()
+                return quart.Response(content, mimetype='application/javascript')
+            return quart.Response('// SDK not found', status=404, mimetype='application/javascript')
+
         @self.route('', methods=['GET'], auth_type=group.AuthType.USER_TOKEN_OR_API_KEY)
         async def _() -> str:
             plugins = await self.ap.plugin_connector.list_plugins()
@@ -173,15 +209,62 @@ class PluginsRouterGroup(group.RouterGroup):
             return quart.Response(icon_data, mimetype=mime_type)
 
         @self.route(
-            '/<author>/<plugin_name>/assets/<filepath>',
+            '/<author>/<plugin_name>/assets/<path:filepath>',
             methods=['GET'],
             auth_type=group.AuthType.NONE,
         )
         async def _(author: str, plugin_name: str, filepath: str) -> quart.Response:
-            asset_data = await self.ap.plugin_connector.get_plugin_assets(author, plugin_name, filepath)
+            asset_path = _normalize_plugin_asset_path(filepath)
+            if asset_path is None:
+                return quart.Response('Asset not found', status=404)
+
+            asset_data = await self.ap.plugin_connector.get_plugin_assets(author, plugin_name, asset_path)
+            if not asset_data.get('asset_base64'):
+                return quart.Response('Asset not found', status=404)
             asset_bytes = base64.b64decode(asset_data['asset_base64'])
             mime_type = asset_data['mime_type']
-            return quart.Response(asset_bytes, mimetype=mime_type)
+            resp = quart.Response(asset_bytes, mimetype=mime_type)
+            # CSP for HTML pages served to sandboxed iframes (opaque origin).
+            # 'self' doesn't work in sandboxed iframes — use actual server origin.
+            if mime_type and mime_type.startswith('text/html'):
+                origin = f'{quart.request.scheme}://{quart.request.host}'
+                resp.headers['Content-Security-Policy'] = (
+                    f'default-src {origin}; '
+                    f"script-src {origin} 'unsafe-inline'; "
+                    f"style-src {origin} 'unsafe-inline'; "
+                    f'img-src {origin} data:; '
+                    f'connect-src {origin}; '
+                    "frame-src 'none'; "
+                    "object-src 'none'"
+                )
+            return resp
+
+        @self.route(
+            '/<author>/<plugin_name>/page-api',
+            methods=['POST'],
+            auth_type=group.AuthType.USER_TOKEN_OR_API_KEY,
+        )
+        async def _(author: str, plugin_name: str) -> str:
+            """Forward a page API request to the plugin."""
+            data = await quart.request.json
+            if not isinstance(data, dict):
+                return self.http_status(400, -1, 'invalid request body')
+
+            page_id = data.get('page_id', '')
+            endpoint = data.get('endpoint', '')
+            method = data.get('method', 'POST')
+            body = data.get('body')
+            if not isinstance(page_id, str) or not isinstance(endpoint, str) or not isinstance(method, str):
+                return self.http_status(400, -1, 'invalid page api request')
+            if not endpoint.startswith('/') or '..' in endpoint:
+                return self.http_status(400, -1, 'invalid endpoint')
+
+            result = await self.ap.plugin_connector.handle_page_api(
+                author, plugin_name, page_id, endpoint, method.upper(), body
+            )
+            if result.get('error'):
+                return self.http_status(400, -1, result['error'])
+            return self.success(data=result.get('data'))
 
         @self.route('/github/releases', methods=['POST'], auth_type=group.AuthType.USER_TOKEN_OR_API_KEY)
         async def _() -> str: