feat: add tools API endpoint and tools-selector form type (#2103)

* feat: add tools API endpoint and tools-selector form type

Backend:
- Add GET /api/v1/tools — list all available tools (plugin + MCP)
- Add GET /api/v1/tools/<tool_name> — get specific tool details

Frontend:
- Add TOOLS_SELECTOR form type for plugin config forms
- Multi-select dialog with tool name and description
- Add PluginTool entity type and API client methods

* fix: remove unused quart import, fix prettier formatting

* style: ruff format tools.py

* chore: bump langbot-plugin to 0.3.7

web/src/app/home/components/dynamic-form/DynamicFormComponent.tsx

@@ -249,6 +249,9 @@ export default function DynamicFormComponent({
           case 'bot-selector':
             fieldSchema = z.string();
             break;
+          case 'tools-selector':
+            fieldSchema = z.array(z.string());
+            break;
           case 'model-fallback-selector':
             fieldSchema = z.object({
               primary: z.string(),