Add code-first responses and hybrid liquid glass

[KanuTomer]

Summary

• make Code the default response style with a separate strict developer schema and inert copyable code cards
• move fail-closed click-through controls onto Copilot with confirmation, persistent recovery guidance, tray/shortcut synchronization, and persistence rollback
• add settings schema v5, Windows Acrylic with shader fallback, rounded native clipping, and a bounded WebGL2 blue-violet liquid-glass layer
• bump the unsigned beta installer to 0.2.0-beta.3

Local validation

• npm audit --audit-level=high — 0 vulnerabilities
• npm run verify — 378/378 Vitest, 33/33 .NET, typechecks, production build
• npm run eval:m4 — 50/50
• npm run eval:m6:preflight — zero network requests
• npm run eval:m7 — 50/50
• npm run test:e2e — 10/10
• npm run package:win
• packaged FTS and helper probes
• two-cycle WASAPI helper smoke
• clean installer lifecycle smoke
• desktop-composited visual review at 100%, 125%, 150%, and 200% device scale

No OpenAI requests or credits were used. This does not accept the outstanding M0–M2 or M5–M8 manual gates.