fix: support bare proxy format (user:pass@host:port) without scheme

Normalize bare proxy strings by prepending http:// before parsing when
@ is present but :// is absent. Tests added for Python and JS.

js/tests/geoip.test.ts

@@ -25,6 +25,17 @@ describe("resolveProxyIp", () => {
   it("returns null for empty string", async () => {
     expect(await resolveProxyIp("")).toBeNull();
   });
+
+  it("returns null for schemeless proxy (shows why normalization is needed)", async () => {
+    // no scheme — new URL() gives empty hostname for both bare formats
+    expect(await resolveProxyIp("user:pass@10.50.96.5:8888")).toBeNull();
+    expect(await resolveProxyIp("10.50.96.5:8888")).toBeNull();
+  });
+
+  it("extracts IP after normalization (http:// prepended by maybeResolveGeoip)", async () => {
+    expect(await resolveProxyIp("http://user:pass@10.50.96.5:8888")).toBe("10.50.96.5");
+    expect(await resolveProxyIp("http://10.50.96.5:8888")).toBe("10.50.96.5");
+  });
 });
 
 describe("COUNTRY_LOCALE_MAP", () => {

js/tests/proxy.test.ts

@@ -82,3 +82,36 @@ describe("proxy dict type", () => {
     }
   });
 });
+
+describe("bare proxy format (user:pass@host:port)", () => {
+  it("extracts credentials from bare format", () => {
+    expect(parseProxyUrl("user:pass@proxy:8080")).toEqual({
+      server: "http://proxy:8080",
+      username: "user",
+      password: "pass",
+    });
+  });
+
+  it("credentials not in server", () => {
+    const r = parseProxyUrl("user:pass@proxy1.example.com:5610");
+    expect(r.server).not.toContain("user");
+    expect(r.server).not.toContain("pass");
+  });
+
+  it("bare username only", () => {
+    const r = parseProxyUrl("user@proxy:8080");
+    expect(r.username).toBe("user");
+    expect(r.password).toBeUndefined();
+    expect(r.server).toBe("http://proxy:8080");
+  });
+
+  it("bare no port", () => {
+    const r = parseProxyUrl("user:pass@proxy.example.com");
+    expect(r.username).toBe("user");
+    expect(r.server).toBe("http://proxy.example.com");
+  });
+
+  it("bare no credentials passes through unchanged", () => {
+    expect(parseProxyUrl("proxy:8080")).toEqual({ server: "proxy:8080" });
+  });
+});

js/tests/puppeteer.test.ts

@@ -13,6 +13,7 @@ vi.mock("../src/download.js", () => ({
 
 vi.mock("../src/geoip.js", () => ({
   resolveProxyGeo: vi.fn().mockResolvedValue({ timezone: null, locale: null }),
+  maybeResolveGeoip: vi.fn().mockResolvedValue({}),
 }));
 
 describe("puppeteer launch", () => {