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", () => {