Add manual opener tool calls to Assistant model and API

- Introduced `manual_opener_tool_calls` field in the Assistant model to support custom tool calls.
- Updated AssistantBase and AssistantUpdate schemas to include the new field.
- Implemented normalization and migration logic for handling manual opener tool calls in the API.
- Enhanced runtime metadata to include manual opener tool calls in responses.
- Updated tests to validate the new functionality and ensure proper handling of tool calls.
- Refactored tool ID normalization to support legacy tool names for backward compatibility.

web/types.ts

@@ -5,6 +5,7 @@ export interface Assistant {
   callCount: number;
   firstTurnMode?: 'bot_first' | 'user_first';
   opener: string;
+  manualOpenerToolCalls?: AssistantOpenerToolCall[];
   generatedOpenerEnabled?: boolean;
   openerAudioEnabled?: boolean;
   openerAudioReady?: boolean;
@@ -29,6 +30,11 @@ export interface Assistant {
   rerankModelId?: string;
 }
 
+export interface AssistantOpenerToolCall {
+  toolName: string;
+  arguments?: string | Record<string, any>;
+}
+
 export interface Voice {
   id: string;
   name: string;