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/src/core/custom-tools/wrapper.ts

@@ -0,0 +1,28 @@
+/**
+ * Wraps CustomTool instances into AgentTool for use with the agent.
+ */
+
+import type { AgentTool } from "@mariozechner/pi-agent-core";
+import type { CustomTool, CustomToolContext, LoadedCustomTool } from "./types.js";
+
+/**
+ * Wrap a CustomTool into an AgentTool.
+ * The wrapper injects the ToolContext into execute calls.
+ */
+export function wrapCustomTool(tool: CustomTool, getContext: () => CustomToolContext): AgentTool {
+	return {
+		name: tool.name,
+		label: tool.label,
+		description: tool.description,
+		parameters: tool.parameters,
+		execute: (toolCallId, params, signal, onUpdate) =>
+			tool.execute(toolCallId, params, signal, onUpdate, getContext()),
+	};
+}
+
+/**
+ * Wrap all loaded custom tools into AgentTools.
+ */
+export function wrapCustomTools(loadedTools: LoadedCustomTool[], getContext: () => CustomToolContext): AgentTool[] {
+	return loadedTools.map((lt) => wrapCustomTool(lt.tool, getContext));
+}