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/settings.payload-rule-platform-options.test.ts

@@ -1,26 +0,0 @@
-import { describe, expect, it } from 'vitest';
-import { PAYLOAD_RULE_PROTOCOL_OPTIONS } from './settings/payloadRuleProtocolOptions.js';
-
-describe('payload rule platform options', () => {
-  it('includes non-codex upstream platforms that payload rules can match in production routing', () => {
-    const values = PAYLOAD_RULE_PROTOCOL_OPTIONS.map((option) => option.value);
-
-    expect(values).toEqual(expect.arrayContaining([
-      '',
-      'codex',
-      'sub2api',
-      'new-api',
-      'one-api',
-      'cliproxyapi',
-      'openai',
-      'claude',
-      'gemini',
-      'gemini-cli',
-      'antigravity',
-      'anyrouter',
-      'done-hub',
-      'one-hub',
-      'veloera',
-    ]));
-  });
-});