feat(user): align profile row values, use edit icon, split subscription card

[zigzagdev]

Summary

• Switch each editable row to a CSS grid (grid-cols-[8rem_1fr_auto]) so the label column has a fixed width and value text starts at the same X position on every row, with the edit affordance flush right
• Replace the "Edit" text button with a pencil icon (EditIcon), keeping the existing aria-label for accessibility
• Increase row padding (px-6 → px-8) for more breathing room
• Widen the profile card (max-w-xl → max-w-2xl)
• Split Subscription (+ the "Upgrade to Paid" link) out of the profile-fields card into its own card — billing status is a different kind of information than editable profile fields

Related

Closes #483

Test plan

• npx tsc --noEmit
• npx jest (16 tests in UserProfileView.test.tsx, no behavior change so none needed updating)
• npm run format:check

[zigzagdev]

Ok