refactor: enhance model capabilities configuration

[chenyme]

Summary

增强模型能力 JSON 的可视化配置与前端参数联动，并统一设置类页面的布局表现。

• 后台模型配置新增「快速配置」入口，可视化维护 defaultOptions 与 optionControls。
• 聊天侧参数配置弹窗会根据模型 capabilitiesJSON.optionControls 自动展示参数控件。
• 保持现有模型参数透传黑白名单规则，前端控件不绕过后端过滤策略。
• 优化 JSON 编辑器主题同步，并处理 Monaco 销毁时偶发的 Canceled 异常。
• 修复文件检索设置页、管理页参数区域、用户设置页宽度不一致和横向滚动问题。
• 用户设置页内容宽度统一为后台设置页同款 1080px。

Change type

• Feature
• Bug fix
• Refactor

Affected areas

• Frontend / UI
• Model routing / providers
• Admin console

Verification

• cd frontend && pnpm lint
• git diff --check

Screenshots, API examples, or logs

Not included.

Configuration, migration, and compatibility notes

No backend API or database migration changes.

Existing capabilitiesJSON remains the single source of truth:

• defaultOptions stores default request options.
• optionControls stores frontend visual control metadata.
• Existing model option allowlist / denylist filtering remains authoritative.

Documentation

• Documentation is not needed for this change.

Security and privacy

• No secrets, tokens, credentials, local config, or personal data are included.
• User data access remains scoped by authenticated user context unless an admin-only path explicitly requires broader access.
• Security-sensitive behavior was reviewed, including provider routing and model option filtering.

Checklist

• Changes are focused and do not include unrelated refactors.
• Tests or static verification were run where practical.
• User-facing behavior, deployment steps, API contracts, or configuration changes are documented.
• Generated artifacts are included only when this project explicitly requires them.
• Caches, build output, .pyc files, .env files, and local storage data are not committed.