feat: add capture profile settings

[kev1n77]

Summary

• add a dedicated Profiles settings view for the versioned active Capture Profile
• edit and validate the Profile name, HTTP(S) Gateway origin, and up to 16 exact additional capture hosts
• fail closed unless capture is paused in Gateway mode, with in-context Pause and Return to Gateway actions
• save through the Tauri runtime command, refill canonical backend values, and restore the built-in OpenAI defaults
• update keyboard, axe, unit, browser fixture, minimum-viewport E2E, progress, and threat-model coverage

Verification

• npm run desktop:check (51 tests passed)
• npm run desktop:build
• npx playwright test e2e/workbench.spec.ts --grep "Capture Profile controls"
• in-app browser verification at desktop and 600x620: no horizontal overflow or console errors; desktop content and dialog scroll heights match; action footer is pinned to the dialog bottom
• full local E2E: the four functional/visual checks, including the new Profile check, passed; the existing thousand-request test exceeded its 2s navigation-start budget because local instrumented Chromium startup took 7.9s. The same baseline passed on PR feat: wire capture profiles into desktop runtime #96 Ubuntu CI.