feat: add Requesty as an OpenAI-compatible provider (#1604)

Add a Requesty provider preset to the provider preset catalog, mirroring the existing OpenRouter preset (base https://router.requesty.ai/v1, default model openai/gpt-4o-mini, OpenAI-compatible).

tests/unit/api/provider-presets-requesty.test.ts

@@ -0,0 +1,57 @@
+import { describe, expect, it } from 'bun:test';
+import { getPresetById, isValidPresetId } from '../../../src/api/services/provider-presets';
+import { PROVIDER_PRESET_IDS } from '../../../src/shared/provider-preset-catalog';
+
+describe('provider-presets-requesty', () => {
+  it('resolves requesty preset id', () => {
+    const preset = getPresetById('requesty');
+    expect(preset?.id).toBe('requesty');
+    expect(preset?.baseUrl).toBe('https://router.requesty.ai/v1');
+    expect(preset?.defaultProfileName).toBe('requesty');
+  });
+
+  it('registers requesty in PROVIDER_PRESET_IDS', () => {
+    expect(PROVIDER_PRESET_IDS).toContain('requesty');
+  });
+
+  it('uses the OpenAI-compatible base URL with a /v1 suffix', () => {
+    const preset = getPresetById('requesty');
+    expect(preset?.baseUrl).toBe('https://router.requesty.ai/v1');
+    expect(preset?.baseUrl.endsWith('/v1')).toBe(true);
+  });
+
+  it('pins a provider/model default (openai/gpt-4o-mini)', () => {
+    const preset = getPresetById('requesty');
+    expect(preset?.defaultModel).toBe('openai/gpt-4o-mini');
+  });
+
+  it('validates requesty preset requires an API key', () => {
+    const preset = getPresetById('requesty');
+    expect(preset?.requiresApiKey).toBe(true);
+  });
+
+  it('is a plain (non-featured) alternative provider', () => {
+    const preset = getPresetById('requesty');
+    expect(preset?.category).toBe('alternative');
+    expect(preset?.featured).toBeUndefined();
+  });
+
+  it('treats requesty as a valid preset id', () => {
+    expect(isValidPresetId('requesty')).toBe(true);
+  });
+
+  it('handles whitespace in requesty preset id', () => {
+    const preset = getPresetById('  requesty  ');
+    expect(preset?.id).toBe('requesty');
+  });
+
+  it('handles uppercase requesty preset id', () => {
+    const preset = getPresetById('REQUESTY');
+    expect(preset?.id).toBe('requesty');
+  });
+
+  it('does not resolve partial or invalid requesty ids', () => {
+    expect(getPresetById('requesty-invalid')).toBeUndefined();
+    expect(isValidPresetId('requesty-invalid')).toBe(false);
+  });
+});