fix(windows): use stdio array in Bun.spawnSync

[lendtrain]

Summary

Fixes the browse daemon failing on Windows with stdio must be an array error.

One-line change: { stdio: 'ignore' } → { stdio: ['ignore', 'ignore', 'ignore'] }

Root Cause

Bun.spawnSync requires stdio to be an array, not a string. The Windows code path at browse/src/cli.ts:239 passed the string form. macOS/Linux take the else branch which already uses an array (['ignore', 'pipe', 'pipe']), so this was never caught.

Before

$ browse goto https://example.com
[browse] Starting server...
[browse] stdio must be an array

After

$ browse goto https://example.com
[browse] Starting server...
Navigated to https://example.com (200)

Test Plan

• Verified fix on Windows 10 Pro with Bun 1.3.11
• Recompiled browse.exe and confirmed end-to-end navigation works

Fixes #454