feat(coding-agent): type ToolCallEvent.input per tool

Matches ToolResultEvent pattern with typed inputs via discriminated union.

- Export *ToolInput types from tool schemas
- Add *ToolCallEvent interfaces for each built-in tool
- Add isToolCallEventType() guard with overloads for built-ins

Direct narrowing (event.toolName === "bash") doesn't work due to
CustomToolCallEvent.toolName: string overlapping with literals.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -3,7 +3,7 @@ import { createWriteStream, existsSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { AgentTool } from "@mariozechner/pi-agent-core";
-import { Type } from "@sinclair/typebox";
+import { type Static, Type } from "@sinclair/typebox";
 import { spawn } from "child_process";
 import { getShellConfig, getShellEnv, killProcessTree } from "../../utils/shell.js";
 import { DEFAULT_MAX_BYTES, DEFAULT_MAX_LINES, formatSize, type TruncationResult, truncateTail } from "./truncate.js";
@@ -21,6 +21,8 @@ const bashSchema = Type.Object({
 	timeout: Type.Optional(Type.Number({ description: "Timeout in seconds (optional, no default timeout)" })),
 });
 
+export type BashToolInput = Static<typeof bashSchema>;
+
 export interface BashToolDetails {
 	truncation?: TruncationResult;
 	fullOutputPath?: string;