fix(app): prevent iOS input zoom without resizing controls

[opencode-agent]

Summary

• apply maximum-scale=1 only on iPhone/iPod so input focus no longer auto-zooms while user pinch zoom remains available
• keep the viewport override current across head mutations and share it with the hosted and enterprise web shells
• remove the coarse-pointer 16px input and 13px placeholder font-size overrides
• authorize both trusted inline startup scripts in the embedded web UI CSP

Checks

• bun typecheck (packages/ui, packages/app, packages/enterprise, packages/cli)
• bun test --only-failures test/web-ui.test.ts (packages/cli)
• bun test --conditions=solid --only-failures --preload ./happydom.ts ./src/theme-preload.test.ts (packages/app)
• bun test ./e2e/performance/unit/desktop-startup.test.ts --only-failures (packages/app)
• app production build via Bun/Vite
• enterprise client and SSR Vite builds; final Nitro packaging stalls in this host environment
• targeted iPhone/Android DOM behavior verification
• targeted Oxlint and Prettier checks

Requested by: @Brendonovich (Brendan via Slack)