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/index.ts

@@ -1,18 +1,48 @@
 export {
 	type BashOperations,
 	type BashToolDetails,
+	type BashToolInput,
 	type BashToolOptions,
 	bashTool,
 	createBashTool,
 } from "./bash.js";
-export { createEditTool, type EditOperations, type EditToolDetails, type EditToolOptions, editTool } from "./edit.js";
-export { createFindTool, type FindOperations, type FindToolDetails, type FindToolOptions, findTool } from "./find.js";
-export { createGrepTool, type GrepOperations, type GrepToolDetails, type GrepToolOptions, grepTool } from "./grep.js";
-export { createLsTool, type LsOperations, type LsToolDetails, type LsToolOptions, lsTool } from "./ls.js";
+export {
+	createEditTool,
+	type EditOperations,
+	type EditToolDetails,
+	type EditToolInput,
+	type EditToolOptions,
+	editTool,
+} from "./edit.js";
+export {
+	createFindTool,
+	type FindOperations,
+	type FindToolDetails,
+	type FindToolInput,
+	type FindToolOptions,
+	findTool,
+} from "./find.js";
+export {
+	createGrepTool,
+	type GrepOperations,
+	type GrepToolDetails,
+	type GrepToolInput,
+	type GrepToolOptions,
+	grepTool,
+} from "./grep.js";
+export {
+	createLsTool,
+	type LsOperations,
+	type LsToolDetails,
+	type LsToolInput,
+	type LsToolOptions,
+	lsTool,
+} from "./ls.js";
 export {
 	createReadTool,
 	type ReadOperations,
 	type ReadToolDetails,
+	type ReadToolInput,
 	type ReadToolOptions,
 	readTool,
 } from "./read.js";
@@ -26,7 +56,13 @@ export {
 	truncateLine,
 	truncateTail,
 } from "./truncate.js";
-export { createWriteTool, type WriteOperations, type WriteToolOptions, writeTool } from "./write.js";
+export {
+	createWriteTool,
+	type WriteOperations,
+	type WriteToolInput,
+	type WriteToolOptions,
+	writeTool,
+} from "./write.js";
 
 import type { AgentTool } from "@mariozechner/pi-agent-core";
 import { type BashToolOptions, bashTool, createBashTool } from "./bash.js";