fix(coding-agent): avoid Windows context file walk hang

closes #6369

packages/coding-agent/CHANGELOG.md

@@ -21,6 +21,7 @@
 - Fixed new session resets to clear cached label timestamps ([#6354](https://github.com/earendil-works/pi/issues/6354)).
 - Fixed auto-retry for Bun fetch socket-drop errors reported as `socket connection was closed`, so transient provider disconnects do not end headless runs without retrying ([#6431](https://github.com/earendil-works/pi/issues/6431)).
 - Fixed `models.json` `modelOverrides` to apply to extension-registered provider models ([#6367](https://github.com/earendil-works/pi/issues/6367)).
+- Fixed project context file discovery to use stable parent traversal on Windows so startup no longer hangs while loading AGENTS.md or CLAUDE.md ([#6369](https://github.com/earendil-works/pi/issues/6369)).
 
 ### Removed
 

packages/coding-agent/src/core/resource-loader.ts

@@ -1,5 +1,5 @@
 import { existsSync, readdirSync, readFileSync, statSync } from "node:fs";
-import { join, resolve, sep } from "node:path";
+import { dirname, join, resolve, sep } from "node:path";
 import chalk from "chalk";
 import { CONFIG_DIR_NAME } from "../config.ts";
 import { loadThemeFromPath, type Theme } from "../modes/interactive/theme/theme.ts";
@@ -101,7 +101,6 @@ export function loadProjectContextFiles(options: {
 	const ancestorContextFiles: Array<{ path: string; content: string }> = [];
 
 	let currentDir = resolvedCwd;
-	const root = resolve("/");
 
 	while (true) {
 		const contextFile = loadContextFileFromDir(currentDir);
@@ -110,9 +109,7 @@ export function loadProjectContextFiles(options: {
 			seenPaths.add(contextFile.path);
 		}
 
-		if (currentDir === root) break;
-
-		const parentDir = resolve(currentDir, "..");
+		const parentDir = dirname(currentDir);
 		if (parentDir === currentDir) break;
 		currentDir = parentDir;
 	}