fix(codex): expose vision settings for Responses providers

[wangziheng437]

Summary

• expose the existing image-input, per-model vision, and vision-routing settings for third-party Responses providers
• keep official OpenAI and native DeepSeek Responses providers read-only where these snapshots do not apply
• synchronize linked API-key provider snapshots and show a restart hint when active Codex/API Service processes may still use the old manifest
• align all localized help text with the existing v1.3.8 behavior: omit unsupported images and continue with text unless a vision route is available
• add regression coverage for UI capability policy, provider snapshot persistence, and Provider Gateway manifest serialization

Validation

• npm run typecheck
• node --test src/utils/codexModelProviderAccountSync.test.ts src/utils/codexProviderPresets.test.ts
• node scripts/check_locales.cjs
• npm run build
• npm exec -- vite build
• git diff --check

Environment limitation

• Rust test compilation was attempted, but this Windows machine does not have the MSVC link.exe prerequisite. The targeted tests did not compile locally and are left for CI.
• cargo fmt --all --check could not run because Windows application control blocked rustfmt (os error 4551).