Align question and message styles with the shared theme

[eivindjonassen]

Summary

• Replace per-component font sizes in question controls and transcript messages with shared typography tokens.
• Use neutral theme colors for question and permission headings, and shared body typography for permission errors.
• Add Dynamic Type ramps to form choices and buttons. Preserve monospace code and shell output, selected states, and danger colors.
• Add regression tests for question, permission, and assistant message styling.

Validation

• pnpm check passed, including 406 mobile tests and both iOS and Android Hermes exports.
• pnpm native:doctor passed all 18 checks.
• Published from the local working tree to the preview OTA channel for iOS and Android, runtime 0.1.5, update group fb07d953-1f6c-4314-867b-9cecd445615d. The user reports applying the update.
• Device visual verification remains pending.