🤖 refactor: remove file_edit_insert tool

The file_edit_insert tool led to more issues than benefits (unreliable line offset calculations and edge cases). Standardize on file_edit_replace_string as the primary file editing tool.

Changes:
- Remove file_edit_insert tool and all references
- Remove from tool definitions and type exports
- Update UI components to only support replace_string and replace_lines
- Update tests and tool policies
- Update integration tests to use file_edit_replace_string

All 987 unit tests pass; typecheck is clean.

Author: root

src/components/Messages/ToolMessage.tsx

@@ -13,8 +13,6 @@ import type {
   BashToolResult,
   FileReadToolArgs,
   FileReadToolResult,
-  FileEditInsertToolArgs,
-  FileEditInsertToolResult,
   FileEditReplaceStringToolArgs,
   FileEditReplaceStringToolResult,
   FileEditReplaceLinesToolArgs,
@@ -61,11 +59,6 @@ function isFileEditReplaceLinesTool(
   return TOOL_DEFINITIONS.file_edit_replace_lines.schema.safeParse(args).success;
 }
 
-function isFileEditInsertTool(toolName: string, args: unknown): args is FileEditInsertToolArgs {
-  if (toolName !== "file_edit_insert") return false;
-  return TOOL_DEFINITIONS.file_edit_insert.schema.safeParse(args).success;
-}
-
 function isProposePlanTool(toolName: string, args: unknown): args is ProposePlanToolArgs {
   if (toolName !== "propose_plan") return false;
   return TOOL_DEFINITIONS.propose_plan.schema.safeParse(args).success;
@@ -134,19 +127,6 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({ message, className, wo
     );
   }
 
-  if (isFileEditInsertTool(message.toolName, message.args)) {
-    return (
-      <div className={className}>
-        <FileEditToolCall
-          toolName="file_edit_insert"
-          args={message.args}
-          result={message.result as FileEditInsertToolResult | undefined}
-          status={message.status}
-        />
-      </div>
-    );
-  }
-
   if (isProposePlanTool(message.toolName, message.args)) {
     return (
       <div className={className}>

src/components/tools/FileEditToolCall.tsx

@@ -1,8 +1,6 @@
 import React from "react";
 import { parsePatch } from "diff";
 import type {
-  FileEditInsertToolArgs,
-  FileEditInsertToolResult,
   FileEditReplaceStringToolArgs,
   FileEditReplaceStringToolResult,
   FileEditReplaceLinesToolArgs,
@@ -24,18 +22,12 @@ import { TooltipWrapper, Tooltip } from "../Tooltip";
 import { DiffContainer, DiffRenderer, SelectableDiffRenderer } from "../shared/DiffRenderer";
 import { KebabMenu, type KebabMenuItem } from "../KebabMenu";
 
-type FileEditOperationArgs =
-  | FileEditReplaceStringToolArgs
-  | FileEditReplaceLinesToolArgs
-  | FileEditInsertToolArgs;
+type FileEditOperationArgs = FileEditReplaceStringToolArgs | FileEditReplaceLinesToolArgs;
 
-type FileEditToolResult =
-  | FileEditReplaceStringToolResult
-  | FileEditReplaceLinesToolResult
-  | FileEditInsertToolResult;
+type FileEditToolResult = FileEditReplaceStringToolResult | FileEditReplaceLinesToolResult;
 
 interface FileEditToolCallProps {
-  toolName: "file_edit_replace_string" | "file_edit_replace_lines" | "file_edit_insert";
+  toolName: "file_edit_replace_string" | "file_edit_replace_lines";
   args: FileEditOperationArgs;
   result?: FileEditToolResult;
   status?: ToolStatus;