Add tool result streaming

- Add AgentToolUpdateCallback type and optional onUpdate callback to AgentTool.execute()
- Add tool_execution_update event with toolCallId, toolName, args, partialResult
- Normalize tool_execution_end to always use AgentToolResult (no more string fallback)
- Bash tool streams truncated rolling buffer output during execution
- ToolExecutionComponent shows last N lines when collapsed (not first N)
- Interactive mode handles tool_execution_update events
- Update RPC docs and ai/agent READMEs

fixes #44

packages/coding-agent/src/core/tools/bash.ts

@@ -35,6 +35,7 @@ export const bashTool: AgentTool<typeof bashSchema> = {
 		_toolCallId: string,
 		{ command, timeout }: { command: string; timeout?: number },
 		signal?: AbortSignal,
+		onUpdate?,
 	) => {
 		return new Promise((resolve, reject) => {
 			const { shell, args } = getShellConfig();
@@ -92,6 +93,20 @@ export const bashTool: AgentTool<typeof bashSchema> = {
 					const removed = chunks.shift()!;
 					chunksBytes -= removed.length;
 				}
+
+				// Stream partial output to callback (truncated rolling buffer)
+				if (onUpdate) {
+					const fullBuffer = Buffer.concat(chunks);
+					const fullText = fullBuffer.toString("utf-8");
+					const truncation = truncateTail(fullText);
+					onUpdate({
+						content: [{ type: "text", text: truncation.content || "" }],
+						details: {
+							truncation: truncation.truncated ? truncation : undefined,
+							fullOutputPath: tempFilePath,
+						},
+					});
+				}
 			};
 
 			// Collect stdout and stderr together