fix: migrate coding-agent tests from fs.rm to removeWithRetries

Migrate 203 test files (356 call sites) from fs.rm/fs.rmSync to
removeWithRetries/removeSyncWithRetries to reduce EBUSY test failures
on Windows. removeWithRetries is now exported from @oh-my-pi/pi-utils.

The migration uses a regex-based approach that:
- Replaces fs.rm(path, { recursive, force }) → removeWithRetries(path)
- Replaces fs.rmSync(path, { recursive, force }) → removeSyncWithRetries(path)
- Replaces fs.rm(path) → removeWithRetries(path) (no options)
- Skips fs.rm/fs.rmSync inside template literals (bun --eval scripts)
- Adds imports to existing @oh-my-pi/pi-utils import or creates new one
- Removes unused fs imports where fs.rm was the only fs usage (4 files)

packages/coding-agent/test/internal-urls/vault-protocol.test.ts

@@ -10,13 +10,14 @@ import {
 	VaultProtocolHandler,
 } from "@oh-my-pi/pi-coding-agent/internal-urls";
 import * as vaultProtocol from "@oh-my-pi/pi-coding-agent/internal-urls/vault-protocol";
+import { removeWithRetries } from "@oh-my-pi/pi-utils";
 
 async function withTempDir<T>(fn: (dir: string) => Promise<T>): Promise<T> {
 	const dir = await fs.mkdtemp(path.join(os.tmpdir(), "vault-protocol-"));
 	try {
 		return await fn(dir);
 	} finally {
-		await fs.rm(dir, { recursive: true, force: true });
+		await removeWithRetries(dir);
 	}
 }