Goal: Windows Tauri Proxy Client

Use Krypton Execution to execute docs/goals/windows-modular-client/PLAN.md.

Core rules:

Treat PLAN.md as the source plan.
Preserve intent, ownership, contract, cutover, evidence, and kill criteria.
Build a separate Tauri 2 Windows desktop app under apps/windows-client.
Do not implement Windows by extending the current Node gateway/client server.
Keep Control App, Proxyfier Layer, and Local sing-box separately installable and operable.
Make external proxy target + ProxiFyre profile apply the MVP.
Keep Local sing-box optional; it must not be required for external target profiles.
Keep generated ProxiFyre and sing-box configs derived from source models.
Capture acceptance evidence from the target user's perspective and record it in EVIDENCE.md.
Say "implemented but unproven" if Windows-only privileged evidence cannot be captured.