refactor: finish strict tool-call typing and mapper dedup

packages/server/src/shared/path-utils.ts

@@ -0,0 +1,17 @@
+export function stripCwdPrefix(filePath: string, cwd?: string): string {
+  if (!cwd || !filePath) {
+    return filePath;
+  }
+
+  const normalizedCwd = cwd.replace(/\\/g, "/").replace(/\/+$/, "");
+  const normalizedPath = filePath.replace(/\\/g, "/");
+  const prefix = `${normalizedCwd}/`;
+
+  if (normalizedPath.startsWith(prefix)) {
+    return normalizedPath.slice(prefix.length);
+  }
+  if (normalizedPath === normalizedCwd) {
+    return ".";
+  }
+  return filePath;
+}

packages/server/src/shared/tool-call-display.ts

@@ -1,4 +1,5 @@
 import type { ToolCallTimelineItem } from "../server/agent/agent-sdk-types.js";
+import { stripCwdPrefix } from "./path-utils.js";
 
 export type ToolCallDisplayInput = Pick<
   ToolCallTimelineItem,
@@ -38,24 +39,6 @@ function humanizeToolName(name: string): string {
     .join(" ");
 }
 
-function stripCwdPrefix(filePath: string, cwd?: string): string {
-  if (!cwd || !filePath) {
-    return filePath;
-  }
-
-  const normalizedCwd = cwd.replace(/\\/g, "/").replace(/\/+$/, "");
-  const normalizedPath = filePath.replace(/\\/g, "/");
-  const prefix = `${normalizedCwd}/`;
-
-  if (normalizedPath.startsWith(prefix)) {
-    return normalizedPath.slice(prefix.length);
-  }
-  if (normalizedPath === normalizedCwd) {
-    return ".";
-  }
-  return filePath;
-}
-
 function formatErrorText(error: unknown): string | undefined {
   if (error === null || error === undefined) {
     return undefined;