feat(ui): paint card Base button red when a custom Base Url is set

[Cmochance]

What

Visual cue on each profile card: the Base button turns red whenever a custom Base Url is set on that profile.

Why

A non-OpenAI Base Url breaks ChatGPT / OAuth accounts — the OAuth callback can't reach the redirected endpoint, so login / refresh fail. The Base button currently looks identical regardless of state, making it easy to forget that a profile's Base Url is overridden when switching.

How

• Reuse the existing `profile-action-button-danger` class (soft red border + hover background — same look as the Delete button) when `profile.openai_base_url` is non-null. No new CSS; theme variables already pick this up across light / dark / etc.
• Tooltip swaps to a new `profileBaseConfigured` copy explaining the OAuth-breakage risk and the workaround (clear Base Url before switching to a ChatGPT / OAuth profile).

i18n

en + zh-CN strings added for `profileBaseConfigured`.

Test plan

• `npx tsc --noEmit` clean.
• `npm run build` produces clean vite output.
• Live: rebuild app, set a Base Url on one card, confirm only that card's Base button shows red and the hover tooltip explains the risk; clear the Base Url, button reverts.

🤖 Generated with Claude Code

[Cmochance]

本地 3-agent review 汇总（pre-push）

按 feedback_pre_push_local_review 默认起 code-reviewer + silent-failure-hunter + pr-test-analyzer 三路并行，结论：clean，可合并。

各 agent 共识

• code-reviewer：条件 class + tooltip 正确只挂在 Base 按钮（data-base-url-profile）上；profile-action-button-danger 是 base.css:1473/2097/2103 已有类，无新 CSS；profileBaseConfigured i18n 在 en + zh-CN 都补齐，locale fallback 不会缺键。
• silent-failure-hunter：truthy 检查 profile.openai_base_url 安全。Rust 写入路径在 mac/win/runtime/profile_actions.rs:27 的 normalize_openai_base_url 会把 trim 后空字符串转 None，所以前端不可能看到 stale ""。preview mock fixture 也都是 null / 真实 URL，无 undefined 漏入。
• pr-test-analyzer：UI 视觉变更，仓库无前端测试基建。但 Rust 侧 profile_actions.rs 已断言"清空 Base URL → 落 None"的契约（见 line 505/572），是这条 UI 条件的回归网。无 gap。

唯一观察（不阻塞）

• 当一个 profile 既被设了 Base URL 又是非 active（可删除）时，卡片上 Delete 和 Base 两个红按钮会同时出现。code-reviewer 确认这是预期视觉警示，可接受。

剩余在你侧

1. 完成 PR description 的 hand-test checklist 最后一项（设 Base URL → 看红按钮 + tooltip → 清空 → 按钮回灰）。
2. 如果想跟 main 当前 head（v1.5.6 + PR fix(login): hold Child handle and reap on cancel to close PID-reuse race #29 的 cancel 修复）合并，可能要先 rebase / 合 PR fix(login): hold Child handle and reap on cancel to close PID-reuse race #29 后再合本 PR；或者本 PR 先合，PR fix(login): hold Child handle and reap on cancel to close PID-reuse race #29 之后会自动 rebase。

🤖 review summary by Claude Code