feat: complete shared platform UI contracts

tests/test_documentation_topic_contract.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import unittest
 
 from govoplan_core.core.modules import (
+    CapabilityDocumentation,
     DocumentationConfigurationDecision,
     DocumentationConfigurationProviderRegistration,
     DocumentationCondition,
@@ -116,6 +117,39 @@ class DocumentationTopicContractTests(unittest.TestCase):
         with self.assertRaisesRegex(RegistryError, "duplicate documentation configuration key"):
             duplicate.validate()
 
+    def test_capability_documentation_is_typed_and_must_match_a_provider(self) -> None:
+        registry = PlatformRegistry()
+        registry.register(ModuleManifest(
+            id="example",
+            name="Example",
+            version="1.0.0",
+            capability_factories={"example.lookup": lambda _context: object()},
+            capability_documentation={
+                "example.lookup": CapabilityDocumentation(
+                    label="Example lookup",
+                    summary="Resolves example records without exposing provider internals.",
+                    contract_version="2",
+                    audience=("module_admin",),
+                ),
+            },
+        ))
+        registry.validate()
+
+        missing_provider = PlatformRegistry()
+        missing_provider.register(ModuleManifest(
+            id="example",
+            name="Example",
+            version="1.0.0",
+            capability_documentation={
+                "example.lookup": CapabilityDocumentation(
+                    label="Example lookup",
+                    summary="Resolves example records.",
+                ),
+            },
+        ))
+        with self.assertRaisesRegex(RegistryError, "does not provide it"):
+            missing_provider.validate()
+
 
 def registry_for(*topics: DocumentationTopic) -> PlatformRegistry:
     registry = PlatformRegistry()