feat(webui): auth and deployment boundary (#435)

Add bind-host assessment that refuses 0.0.0.0/:: without override,
warns on non-loopback binds, and documents internal-only MVP serving.
Health endpoint exposes deployment metadata; docs cover Access/VPN/WARP
and runtime env assumptions without embedding secrets in the client.

Closes #435

tests/test_webui_deployment_boundary.py

@@ -0,0 +1,106 @@
+"""Tests for web UI deployment and auth boundary (#435)."""
+import os
+import subprocess
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from starlette.testclient import TestClient
+
+from webui.app import create_app
+from webui.deployment_boundary import (
+    assess_bind_host,
+    runtime_assumptions,
+    scan_text_for_client_secrets,
+)
+
+
+class TestBindAssessment(unittest.TestCase):
+    def test_loopback_is_safe(self):
+        for host in ("127.0.0.1", "localhost", "::1"):
+            with self.subTest(host=host):
+                result = assess_bind_host(host)
+                self.assertEqual(result.disposition, "safe")
+
+    def test_all_interfaces_refused_by_default(self):
+        for host in ("0.0.0.0", "::", "*"):
+            with self.subTest(host=host):
+                result = assess_bind_host(host)
+                self.assertEqual(result.disposition, "refuse")
+
+    def test_all_interfaces_allowed_with_override(self):
+        prior = os.environ.pop("WEBUI_ALLOW_PUBLIC_BIND", None)
+        try:
+            os.environ["WEBUI_ALLOW_PUBLIC_BIND"] = "1"
+            result = assess_bind_host("0.0.0.0")
+            self.assertEqual(result.disposition, "warn")
+        finally:
+            os.environ.pop("WEBUI_ALLOW_PUBLIC_BIND", None)
+            if prior is not None:
+                os.environ["WEBUI_ALLOW_PUBLIC_BIND"] = prior
+
+    def test_non_loopback_warns_without_override(self):
+        prior = os.environ.pop("WEBUI_ALLOW_REMOTE_BIND", None)
+        try:
+            os.environ.pop("WEBUI_ALLOW_REMOTE_BIND", None)
+            result = assess_bind_host("192.168.1.10")
+            self.assertEqual(result.disposition, "warn")
+        finally:
+            if prior is not None:
+                os.environ["WEBUI_ALLOW_REMOTE_BIND"] = prior
+
+    def test_runtime_assumptions_exclude_secrets(self):
+        assumptions = runtime_assumptions()
+        blob = " ".join(str(v) for v in assumptions.values())
+        self.assertNotIn("GITEA_TOKEN", blob)
+        self.assertIn("internal-operator-console", assumptions["deployment_mode"])
+
+
+class TestDeploymentRoutes(unittest.TestCase):
+    def setUp(self):
+        self.client = TestClient(create_app(bind_host="127.0.0.1"))
+
+    def test_health_includes_deployment_metadata(self):
+        response = self.client.get("/health")
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertIn("deployment", data)
+        deployment = data["deployment"]
+        self.assertEqual(deployment["mode"], "internal-operator-console")
+        self.assertEqual(deployment["mvp_auth"], "none")
+        self.assertEqual(deployment["bind"]["disposition"], "safe")
+        self.assertIn("runtime_assumptions", deployment)
+
+    def test_rendered_pages_contain_no_embedded_secrets(self):
+        for path in ("/", "/projects", "/prompts", "/queue"):
+            with self.subTest(path=path):
+                text = self.client.get(path).text
+                self.assertEqual(scan_text_for_client_secrets(text), [])
+
+
+class TestStartupRefusal(unittest.TestCase):
+    def test_refuses_all_interface_bind(self):
+        env = {**os.environ, "WEBUI_HOST": "0.0.0.0"}
+        env.pop("WEBUI_ALLOW_PUBLIC_BIND", None)
+        repo_root = Path(__file__).resolve().parent.parent
+        result = subprocess.run(
+            [sys.executable, "-m", "webui"],
+            cwd=repo_root,
+            env=env,
+            capture_output=True,
+            text=True,
+            timeout=3,
+        )
+        self.assertEqual(result.returncode, 1)
+
+
+class TestClientSecretScanner(unittest.TestCase):
+    def test_detects_token_like_content(self):
+        findings = scan_text_for_client_secrets("var x = GITEA_TOKEN_PRGS")
+        self.assertTrue(findings)
+
+
+if __name__ == "__main__":
+    unittest.main()