Goal: Windows Local Sing-Box

Use Krypton Execution to execute docs/goals/windows-local-singbox/PLAN.md.

Core rules:

Treat PLAN.md as the source plan.
Preserve intent, ownership, contract, cutover, evidence, and kill criteria.
Implement the feature as the existing optional Local sing-box component, not as a new unrelated component id.
Keep external proxy flow working without Local sing-box.
Do not add hidden installation during profile apply.
Do not import or call the root Node server from the Windows client.
Capture acceptance evidence from the target perspective and record it in EVIDENCE.md.
Say "implemented but unproven" if elevated Windows service evidence cannot be captured.