fix: increase e2e test step timeout on Windows to fix flaky CI (#252)

## Summary
- Increases the per-step timeout for e2e snapshot tests from 20s to 60s
on Windows, while keeping 20s on Unix
- Windows CI runners using Git Bash have significantly more overhead for
shell startup and process execution
- The 20-second timeout was frequently exceeded, causing flaky
`[timeout]` failures in tests like `summary-output` and
`filter-unmatched`

## Failure patterns observed
| Pattern | Tests affected | Frequency |
|---------|---------------|-----------|
| `[timeout]` on first step | `summary-output`, `filter-unmatched` |
Most common (3+ occurrences) |
| `[127] command not found` | `exit-codes` | Occasional |

## Test plan
- [x] Compiles locally (`cargo check -p vite_task_bin --test
e2e_snapshots`)
- [ ] Validate by re-running Windows CI at least 10 times to confirm
flakiness is resolved

https://claude.ai/code/session_01VzFJkUBQ9t6zTmH7ZJFXgt

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: branchseer

crates/vite_task_bin/tests/e2e_snapshots/main.rs

@@ -17,8 +17,10 @@ use vite_path::{AbsolutePath, AbsolutePathBuf, RelativePathBuf};
 use vite_str::Str;
 use vite_workspace::find_workspace_root;
 
-/// Timeout for each step in e2e tests
-const STEP_TIMEOUT: Duration = Duration::from_secs(20);
+/// Timeout for each step in e2e tests.
+/// Windows CI needs a longer timeout due to Git Bash startup overhead and slower I/O.
+const STEP_TIMEOUT: Duration =
+    if cfg!(windows) { Duration::from_secs(60) } else { Duration::from_secs(20) };
 
 /// Screen size for the PTY terminal. Large enough to avoid line wrapping.
 const SCREEN_SIZE: ScreenSize = ScreenSize { rows: 500, cols: 500 };