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/pages/modelTester.debug-panel.architecture.test.tsx

@@ -1,18 +0,0 @@
-import { describe, expect, it } from 'vitest';
-import { readFileSync } from 'node:fs';
-import { resolve } from 'node:path';
-
-describe('ModelTester debug panel extraction', () => {
-  it('delegates the debug sidebar to a dedicated model-tester component', () => {
-    const source = readFileSync(resolve(process.cwd(), 'src/web/pages/ModelTester.tsx'), 'utf8').replace(/\r\n/g, '\n');
-
-    expect(source).toContain("import DebugPanel from './model-tester/DebugPanel.js'");
-    expect(source).not.toContain('时间线');
-  });
-
-  it('keeps the debug timestamp prop aligned with the ISO string state used by ModelTester', () => {
-    const source = readFileSync(resolve(process.cwd(), 'src/web/pages/model-tester/DebugPanel.tsx'), 'utf8').replace(/\r\n/g, '\n');
-
-    expect(source).toContain('debugTimestamp: string | null;');
-  });
-});