Rework custom tools API with CustomToolContext

- CustomAgentTool renamed to CustomTool
- ToolAPI renamed to CustomToolAPI
- ToolContext renamed to CustomToolContext
- ToolSessionEvent renamed to CustomToolSessionEvent
- Added CustomToolContext parameter to execute() and onSession()
- CustomToolFactory now returns CustomTool<any, any> for type compatibility
- dispose() replaced with onSession({ reason: 'shutdown' })
- Added wrapCustomTool() to convert CustomTool to AgentTool
- Session exposes setToolUIContext() instead of leaking internals
- Fix ToolExecutionComponent to sync with toolOutputExpanded state
- Update all custom tool examples for new API

packages/coding-agent/examples/custom-tools/hello/index.ts

@@ -10,9 +10,10 @@ const factory: CustomToolFactory = (_pi) => ({
 	}),
 
 	async execute(_toolCallId, params) {
+		const { name } = params as { name: string };
 		return {
-			content: [{ type: "text", text: `Hello, ${params.name}!` }],
-			details: { greeted: params.name },
+			content: [{ type: "text", text: `Hello, ${name}!` }],
+			details: { greeted: name },
 		};
 	},
 });