Expose full tool result content and details in hook tool_result event

Breaking change: ToolResultEvent now exposes content and typed details
instead of just a result string. Hook handlers returning { result: ... }
must change to { content: [...] }.

- ToolResultEvent is now a discriminated union based on toolName
- Each built-in tool has typed details (BashToolDetails, etc.)
- Export tool details types and TruncationResult
- Update hooks.md documentation

Closes #233

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

@@ -21,7 +21,7 @@ const bashSchema = Type.Object({
 	timeout: Type.Optional(Type.Number({ description: "Timeout in seconds (optional, no default timeout)" })),
 });
 
-interface BashToolDetails {
+export interface BashToolDetails {
 	truncation?: TruncationResult;
 	fullOutputPath?: string;
 }

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

@@ -18,7 +18,7 @@ const findSchema = Type.Object({
 
 const DEFAULT_LIMIT = 1000;
 
-interface FindToolDetails {
+export interface FindToolDetails {
 	truncation?: TruncationResult;
 	resultLimitReached?: number;
 }

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

@@ -31,7 +31,7 @@ const grepSchema = Type.Object({
 
 const DEFAULT_LIMIT = 100;
 
-interface GrepToolDetails {
+export interface GrepToolDetails {
 	truncation?: TruncationResult;
 	matchLimitReached?: number;
 	linesTruncated?: boolean;

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

@@ -1,9 +1,10 @@
-export { bashTool } from "./bash.js";
+export { type BashToolDetails, bashTool } from "./bash.js";
 export { editTool } from "./edit.js";
-export { findTool } from "./find.js";
-export { grepTool } from "./grep.js";
-export { lsTool } from "./ls.js";
-export { readTool } from "./read.js";
+export { type FindToolDetails, findTool } from "./find.js";
+export { type GrepToolDetails, grepTool } from "./grep.js";
+export { type LsToolDetails, lsTool } from "./ls.js";
+export { type ReadToolDetails, readTool } from "./read.js";
+export type { TruncationResult } from "./truncate.js";
 export { writeTool } from "./write.js";
 
 import { bashTool } from "./bash.js";

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

@@ -12,7 +12,7 @@ const lsSchema = Type.Object({
 
 const DEFAULT_LIMIT = 500;
 
-interface LsToolDetails {
+export interface LsToolDetails {
 	truncation?: TruncationResult;
 	entryLimitReached?: number;
 }

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

@@ -13,7 +13,7 @@ const readSchema = Type.Object({
 	limit: Type.Optional(Type.Number({ description: "Maximum number of lines to read" })),
 });
 
-interface ReadToolDetails {
+export interface ReadToolDetails {
 	truncation?: TruncationResult;
 }