🛡️ Sentinel: [MEDIUM] Fix SecurityError crash from strict privacy modes

[seonghobae]

🚨 Severity: MEDIUM
💡 Vulnerability: Unhandled SecurityError exceptions when accessing localStorage in strict browser privacy modes (e.g., when cookies are blocked).
🎯 Impact: If unhandled, this crashes the executing script, preventing the language switch and potentially other interactions on the page for privacy-conscious users.
🔧 Fix: Wrapped localStorage.getItem and localStorage.setItem in try-catch blocks to fail securely and fall back to sensible defaults. Added node_modules to .gitignore.
✅ Verification: Tested locally with a script that simulates localStorage throwing a SecurityError and verified the application handles it gracefully without crashing.

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PR created automatically by Jules for task 11023072119535347779 started by @seonghobae

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[github-actions]

OpenCode Review Overview

• Head SHA: 2b087f7dc1c10b85ff14a645086e47bbdd4c27cb
• Workflow run: 27907350996
• Workflow attempt: 1
• Gate result: APPROVE (exit 0)

[opencode-agent]

OpenCode Agent approved this PR.

The changes address security vulnerabilities and improve robustness, particularly around localStorage usage in strict privacy modes. The diff is well-contained and follows best practices for secure coding.

• Result: APPROVE
• Reason: No blockers found
• Head SHA: 2b087f7dc1c10b85ff14a645086e47bbdd4c27cb
• Workflow run: 27907350996
• Workflow attempt: 1