fix(integrations): add zed to discovery catalog.json (#3266)

zed is registered, registrar-aligned and registry-tested, but it was the
only one of the 34 integrations absent from integrations/catalog.json,
making it undiscoverable through the discovery manifest. Add the missing
'zed' entry (mirroring the sibling skills entries) and a registry<->catalog
parity regression test so a future integration can't silently drift.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

integrations/catalog.json

@@ -299,6 +299,15 @@
       "author": "spec-kit-core",
       "repository": "https://github.com/github/spec-kit",
       "tags": ["cli", "skills", "z-ai"]
+    },
+    "zed": {
+      "id": "zed",
+      "name": "Zed",
+      "version": "1.0.0",
+      "description": "Zed editor skills-based integration",
+      "author": "spec-kit-core",
+      "repository": "https://github.com/github/spec-kit",
+      "tags": ["ide", "skills"]
     }
   }
 }

tests/integrations/test_registry.py

@@ -244,3 +244,26 @@ class TestMultiInstallSafeContracts:
                 f"{initial} and {additional} are declared multi-install safe but both manage "
                 f"these files: {sorted(initial_files & additional_files)}"
             )
+
+
+class TestCatalogParity:
+    """The discovery catalog must list every registered integration."""
+
+    def test_every_registered_integration_is_in_catalog(self):
+        """``integrations/catalog.json`` must cover every registry key.
+
+        The catalog is the discovery manifest; an integration that is
+        registered, registrar-aligned and registry-tested but missing from
+        the catalog is undiscoverable through it. ``generic`` is exempt —
+        it is the no-fixed-directory fallback, not a catalogued agent.
+        """
+        from pathlib import Path
+
+        repo_root = Path(__file__).resolve().parents[2]
+        catalog = json.loads(
+            (repo_root / "integrations" / "catalog.json").read_text(encoding="utf-8")
+        )
+        catalogued = set(catalog["integrations"])
+        registered = set(INTEGRATION_REGISTRY) - {"generic"}
+        missing = sorted(registered - catalogued)
+        assert not missing, f"integrations missing from catalog.json: {missing}"