fix(http): respect port numbers in NO_PROXY environment variable (#26347)

## Summary
- Fix NO_PROXY environment variable to properly respect port numbers
like Node.js and curl do
- Previously `NO_PROXY=localhost:1234` would bypass proxy for all
requests to localhost regardless of port
- Now entries with ports (e.g., `localhost:8080`) do exact host:port
matching, while entries without ports continue to use suffix matching

## Test plan
- Added tests in `test/js/bun/http/proxy.test.js` covering:
  - [x] Bypass proxy when NO_PROXY matches host:port exactly
  - [x] Use proxy when NO_PROXY has different port  
- [x] Bypass proxy when NO_PROXY has host only (no port) - existing
behavior preserved
  - [x] Handle NO_PROXY with multiple entries including port
- Verified existing proxy tests still pass

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>

test/js/bun/http/proxy.test.js

@@ -15,10 +15,17 @@ beforeAll(() => {
 
       // simple http proxy
       if (request.url.startsWith("http://")) {
-        return await fetch(request.url, {
+        const response = await fetch(request.url, {
           method: request.method,
           body: await request.text(),
         });
+        // Add marker header to indicate request went through proxy
+        const headers = new Headers(response.headers);
+        headers.set("x-proxy-used", "1");
+        return new Response(response.body, {
+          status: response.status,
+          headers,
+        });
       }
 
       // no TLS support here
@@ -257,4 +264,129 @@ describe.concurrent(() => {
     }
     expect(exitCode).toBe(0);
   });
+
+  // Test that NO_PROXY respects port numbers like Node.js and curl do
+  describe("NO_PROXY port handling", () => {
+    it("should bypass proxy when NO_PROXY matches host:port exactly", async () => {
+      // NO_PROXY includes the exact host:port, should bypass proxy
+      const {
+        exited,
+        stdout,
+        stderr: stderrStream,
+      } = Bun.spawn({
+        cmd: [
+          bunExe(),
+          "-e",
+          `const resp = await fetch("http://localhost:${server.port}/test"); console.log(resp.headers.get("x-proxy-used") || "no-proxy");`,
+        ],
+        env: {
+          ...bunEnv,
+          http_proxy: `http://localhost:${proxy.port}`,
+          NO_PROXY: `localhost:${server.port}`,
+        },
+        stdout: "pipe",
+        stderr: "pipe",
+      });
+
+      const [exitCode, out, stderr] = await Promise.all([exited, stdout.text(), stderrStream.text()]);
+      if (exitCode !== 0) {
+        console.error("stderr:", stderr);
+      }
+      // Should connect directly, not through proxy (no x-proxy-used header)
+      expect(out.trim()).toBe("no-proxy");
+      expect(exitCode).toBe(0);
+    });
+
+    it("should use proxy when NO_PROXY has different port", async () => {
+      const differentPort = server.port + 1000;
+      // NO_PROXY includes a different port, should NOT bypass proxy
+      const {
+        exited,
+        stdout,
+        stderr: stderrStream,
+      } = Bun.spawn({
+        cmd: [
+          bunExe(),
+          "-e",
+          `const resp = await fetch("http://localhost:${server.port}/test"); console.log(resp.headers.get("x-proxy-used") || "no-proxy");`,
+        ],
+        env: {
+          ...bunEnv,
+          http_proxy: `http://localhost:${proxy.port}`,
+          NO_PROXY: `localhost:${differentPort}`,
+        },
+        stdout: "pipe",
+        stderr: "pipe",
+      });
+
+      const [exitCode, out, stderr] = await Promise.all([exited, stdout.text(), stderrStream.text()]);
+      if (exitCode !== 0) {
+        console.error("stderr:", stderr);
+      }
+      // The proxy adds x-proxy-used header, verify it was used
+      expect(out.trim()).toBe("1");
+      expect(exitCode).toBe(0);
+    });
+
+    it("should bypass proxy when NO_PROXY has host only (no port)", async () => {
+      // NO_PROXY includes just the host (no port), should bypass proxy for all ports
+      const {
+        exited,
+        stdout,
+        stderr: stderrStream,
+      } = Bun.spawn({
+        cmd: [
+          bunExe(),
+          "-e",
+          `const resp = await fetch("http://localhost:${server.port}/test"); console.log(resp.headers.get("x-proxy-used") || "no-proxy");`,
+        ],
+        env: {
+          ...bunEnv,
+          http_proxy: `http://localhost:${proxy.port}`,
+          NO_PROXY: `localhost`,
+        },
+        stdout: "pipe",
+        stderr: "pipe",
+      });
+
+      const [exitCode, out, stderr] = await Promise.all([exited, stdout.text(), stderrStream.text()]);
+      if (exitCode !== 0) {
+        console.error("stderr:", stderr);
+      }
+      // Should connect directly, not through proxy (no x-proxy-used header)
+      expect(out.trim()).toBe("no-proxy");
+      expect(exitCode).toBe(0);
+    });
+
+    it("should handle NO_PROXY with multiple entries including port", async () => {
+      const differentPort = server.port + 1000;
+      // NO_PROXY includes multiple entries, one of which matches exactly
+      const {
+        exited,
+        stdout,
+        stderr: stderrStream,
+      } = Bun.spawn({
+        cmd: [
+          bunExe(),
+          "-e",
+          `const resp = await fetch("http://localhost:${server.port}/test"); console.log(resp.headers.get("x-proxy-used") || "no-proxy");`,
+        ],
+        env: {
+          ...bunEnv,
+          http_proxy: `http://localhost:${proxy.port}`,
+          NO_PROXY: `example.com, localhost:${differentPort}, localhost:${server.port}`,
+        },
+        stdout: "pipe",
+        stderr: "pipe",
+      });
+
+      const [exitCode, out, stderr] = await Promise.all([exited, stdout.text(), stderrStream.text()]);
+      if (exitCode !== 0) {
+        console.error("stderr:", stderr);
+      }
+      // Should connect directly, not through proxy (no x-proxy-used header)
+      expect(out.trim()).toBe("no-proxy");
+      expect(exitCode).toBe(0);
+    });
+  });
 });