fix(providers): remove Qwen provider support

Qwen OAuth flow (portal.qwen.ai) stopped working reliably; drop the
executor, registry entry, OAuth provider/service, token refresh
profile, usage handler, and related test coverage and baselines.

tests/unit/codex-refresh-token.test.js

@@ -151,7 +151,6 @@ describe("Codex Refresh Token", () => {
       expect(getRefreshLeadMs("codex")).toBe(5 * 24 * 60 * 60 * 1000);   // 5 days
       expect(getRefreshLeadMs("claude")).toBe(4 * 60 * 60 * 1000);       // 4 hours
       expect(getRefreshLeadMs("iflow")).toBe(24 * 60 * 60 * 1000);       // 24 hours
-      expect(getRefreshLeadMs("qwen")).toBe(20 * 60 * 1000);             // 20 minutes
       expect(getRefreshLeadMs("kimi")).toBe(5 * 60 * 1000);              // 5 minutes
       expect(getRefreshLeadMs("kimi-coding")).toBe(5 * 60 * 1000);       // legacy alias
       expect(getRefreshLeadMs("antigravity")).toBe(5 * 60 * 1000);       // 5 minutes