refactor: purge Node.js, Rust is the one true backend

- Moved boosapi-rs/* to repo root
- Deleted all Node.js source (src/server/, src/web/, scripts/)
- Deleted node_modules, package.json, tsconfig, vite.config
- Updated .gitignore and AGENTS.md for Rust-only stack
- Fixed static file path for frontend dist/web/
- Dockerfile stays the same (already Rust-only)
- Kept dist/web/ for Rust static serving

src/web/i18n.test.ts

@@ -1,47 +0,0 @@
-import { describe, expect, it } from 'vitest';
-import { translateText } from './i18n.js';
-
-describe('translateText', () => {
-  it('keeps zh text unchanged in zh mode', () => {
-    expect(translateText('模型广场', 'zh')).toBe('模型广场');
-  });
-
-  it('translates exact key in en mode', () => {
-    expect(translateText('模型广场', 'en')).toBe('Model Marketplace');
-  });
-
-  it('supports phrase replacement for mixed text', () => {
-    expect(translateText('覆盖槽位 3', 'en')).toBe('Coverage Slots 3');
-    expect(translateText('共 12 个模型', 'en')).toBe('Total 12 models');
-  });
-
-  it('never returns Chinese characters in strict en mode', () => {
-    const samples = [
-      '站点已禁用',
-      '缓存清理后重建失败：unknown error',
-      '签到任务执行中，请稍后查看签到日志',
-    ];
-
-    for (const sample of samples) {
-      expect(translateText(sample, 'en')).not.toMatch(/[\u3400-\u9fff]/);
-    }
-  });
-
-  it('uses concrete english translations instead of fallback for common runtime text', () => {
-    expect(translateText('切换到中文', 'en')).toBe('Switch to Chinese');
-    expect(translateText('中', 'en')).toBe('ZH');
-
-    const samples = [
-      '站点已禁用',
-      '签到任务执行中，请稍后查看签到日志',
-      '下游访问令牌至少 6 位（含 sk-）',
-      '路由重建任务执行中，请稍后查看程序日志',
-    ];
-
-    for (const sample of samples) {
-      const translated = translateText(sample, 'en');
-      expect(translated).not.toBe('Untranslated');
-      expect(translated).not.toMatch(/[\u3400-\u9fff]/);
-    }
-  });
-});