fix: restore frontend source code (src/web/) that was accidentally deleted

Frontend source is needed for development/building the SPA.
Only Node.js runtime server code should be removed.

src/web/pages/settings.payload-rule-platform-options.test.ts

@@ -0,0 +1,26 @@
+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',
+    ]));
+  });
+});