Add response copy controls and native iOS text selection

[eivindjonassen]

Summary

• Add a copy icon below assistant responses and copy controls on code blocks, with a two-second Copied confirmation and retry feedback.
• Add an Apple-only Expo module using a non-editable, selectable UITextView for native selection handles and partial-range copying. Preserve formatting and route link taps through existing confirmation callbacks.
• Keep Android's selectable Text renderer and provide a fallback for older iOS builds without the native module.
• Bump runtime to 0.1.5, iOS build 8, and Android version code 7.

Verification

• pnpm check passed, including 377 mobile tests and both Hermes exports.
• pnpm native:doctor passed all 18 checks.
• Apple autolinking resolves the new module.
• Native compilation and physical-device verification are pending. Selection is scoped to each rendered text block or table cell.
• iOS selection requires installation of a new native build; OTA alone cannot add the module.

Preview builds

Both archives were uploaded from this source before committing; EAS build metadata may reference the parent commit.

• iOS: https://expo.dev/accounts/omnicus/projects/o5s-code/builds/63bc0f6a-fd44-4348-97e5-a5c0f10e73e8
• Android: https://expo.dev/accounts/omnicus/projects/o5s-code/builds/12155aa6-2d8a-4776-ae45-c7ba4bef40ed

[eivindjonassen]

Both native preview builds completed successfully: iOS 0.1.5 build 8 and Android 0.1.5 build 7. This confirms cloud native compilation; physical-device selection verification remains pending.

• Install iOS preview
• Install Android preview