feat: add lease and collision visibility to web UI (Closes #433)

Adds read-only /leases and /api/leases routes for issue claim inventory,
reviewer PR lease comments, duplicate PR/branch warnings, and local issue
lock visibility without acquire/release mutations.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

tests/test_webui_lease_visibility.py

@@ -0,0 +1,94 @@
+"""Tests for web UI lease visibility (#433)."""
+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.lease_loader import (
+    _duplicate_branch_warnings,
+    _duplicate_pr_warnings,
+    load_lease_snapshot,
+    parse_reviewer_lease_comment,
+    snapshot_to_dict,
+)
+
+
+class TestLeaseLoader(unittest.TestCase):
+    def test_parse_reviewer_lease_comment(self):
+        body = (
+            "<!-- mcp-review-lease:v1 -->\n"
+            "pr: #42\n"
+            "reviewer_identity: sysadmin\n"
+            "profile: prgs-reviewer\n"
+            "phase: validating\n"
+            "expires_at: 2026-07-07T20:00:00Z\n"
+        )
+        parsed = parse_reviewer_lease_comment(body)
+        self.assertIsNotNone(parsed)
+        assert parsed is not None
+        self.assertEqual(parsed["pr_number"], 42)
+        self.assertEqual(parsed["phase"], "validating")
+
+    def test_duplicate_pr_warnings(self):
+        raw_prs = [
+            {"number": 1, "title": "Closes #99", "body": ""},
+            {"number": 2, "title": "fixes #99", "body": ""},
+        ]
+        warnings = _duplicate_pr_warnings(raw_prs)
+        self.assertEqual(len(warnings), 1)
+        self.assertEqual(warnings[0].issue_number, 99)
+        self.assertEqual(warnings[0].pr_numbers, (1, 2))
+
+    def test_duplicate_branch_warnings(self):
+        warnings = _duplicate_branch_warnings([
+            "feat/issue-12-a",
+            "feat/issue-12-b",
+            "master",
+        ])
+        self.assertEqual(len(warnings), 1)
+        self.assertEqual(warnings[0].issue_number, 12)
+
+    def test_load_snapshot_with_injected_fetch(self):
+        def fetch_prs(_h, _o, _r, _a):
+            return ([], None)
+
+        def fetch_issues(_h, _o, _r, _a):
+            return ([], None)
+
+        snapshot = load_lease_snapshot(
+            fetch_prs=fetch_prs,
+            fetch_issues=fetch_issues,
+            fetch_comments=lambda *_a, **_k: [],
+            issue_lock_path=str(Path("/nonexistent/lock.json")),
+        )
+        data = snapshot_to_dict(snapshot)
+        self.assertIn("claim_inventory", data)
+        self.assertIn("collision_history", data)
+
+
+class TestLeaseRoutes(unittest.TestCase):
+    def setUp(self):
+        self.client = TestClient(create_app())
+
+    def test_leases_page_renders(self):
+        response = self.client.get("/leases")
+        self.assertEqual(response.status_code, 200)
+        self.assertIn("Leases", response.text)
+        self.assertIn("Collision warnings", response.text)
+        self.assertNotIn("child issue", response.text.lower())
+
+    def test_api_leases_json(self):
+        response = self.client.get("/api/leases")
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertIn("claim_inventory", data)
+        self.assertIn("duplicate_prs", data)
+        self.assertIn("reviewer_leases", data)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_webui_skeleton.py

@@ -46,10 +46,14 @@ class TestWebuiSkeleton(unittest.TestCase):
         self.assertEqual(response.status_code, 200)
         self.assertIn("Gitea-Tools", response.text)
 
+    def test_leases_is_implemented(self):
+        response = self.client.get("/leases")
+        self.assertEqual(response.status_code, 200)
+        self.assertIn("Leases", response.text)
+        self.assertIn("Collision warnings", response.text)
+
     def test_extra_stub_routes(self):
-        for path in ("/worktrees", "/leases"):
-            with self.subTest(path=path):
-                self.assertEqual(self.client.get(path).status_code, 200)
+        self.assertEqual(self.client.get("/worktrees").status_code, 200)
 
     def test_post_is_rejected(self):
         response = self.client.post("/health")
@@ -62,10 +66,10 @@ class TestWebuiSkeleton(unittest.TestCase):
         self.assertIn("Live queue", response.text)
 
     def test_nav_links_on_all_pages(self):
-        for path in ("/", "/queue", "/projects", "/prompts", "/runtime", "/audit"):
+        for path in ("/", "/queue", "/projects", "/prompts", "/runtime", "/audit", "/leases"):
             with self.subTest(path=path):
                 text = self.client.get(path).text
-                for href in ("/queue", "/projects", "/prompts", "/runtime", "/audit"):
+                for href in ("/queue", "/projects", "/prompts", "/runtime", "/audit", "/leases"):
                     self.assertIn(f'href="{href}"', text)