fix(windows): suppress console flashes and align project tabs

[Mucheen]

Summary

• prevent Windows language-server launches from opening visible background console windows
• prevent the registry-based font query from flashing a console while keeping explicit ConPTY terminals unchanged
• vertically center project-tab close controls with the folder icon and project name
• add focused regression coverage for both process flags and tab alignment

Verification

• focused and full Rust tests
• scripts/verify-windows-boundaries.ps1
• bun run typecheck
• targeted frontend lint and project-tab component test
• bun run build
• native Windows debug build and real Tauri-window runtime/visual checks

Related to #132