fix(browser): add --no-sandbox for root user on Linux/WSL2

[furkankoykiran]

Fixes #1364.

When running as root on Linux or WSL2, Chromium exits immediately because its sandbox can't initialize for the root user. browser-manager.ts already skips the sandbox under CI and CONTAINER, but root was missing from that check.

Change

// before
if (process.env.CI || process.env.CONTAINER) {
  launchArgs.push('--no-sandbox');
}

// after
const isRoot = typeof process.getuid === 'function' && process.getuid() === 0;
if (process.env.CI || process.env.CONTAINER || isRoot) {
  launchArgs.push('--no-sandbox');
}

The typeof process.getuid === 'function' guard keeps this safe on Windows where getuid is not defined.

Test

# Before fix (as root, WSL2)
B=~/.claude/skills/gstack/browse/dist/browse
$B goto https://example.com
# [browse] FATAL: Chromium process crashed or was killed. Server exiting.

# After fix
$B goto https://example.com
# Navigated to https://example.com (200)

---

^{Need help on this PR? Tag @codesmith with what you need.}

• Let Codesmith autofix CI failures and bot reviews