fix(github): match repository bindings case-insensitively (#7982)

GitHub owner and repository names are case-insensitive, but the agent
registry indexed and looked up bindings by the raw repo string. A
binding for acme/widget never matched webhooks for Acme/Widget, so the
event was dropped without an error. Lowercase the repo on both sides.

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/app/gateway/github/registry.py

@@ -95,7 +95,7 @@ def _build_index(agents: list[tuple[str, AgentConfig]]) -> _Registry:
                     # it is here, so this branch is unreachable. Keep the
                     # guard for type-checker happiness.
                     continue
-                index.setdefault((binding.repo, event), []).append(GitHubAgentMatch(user_id=user_id, agent=cfg, trigger=resolved))
+                index.setdefault((binding.repo.lower(), event), []).append(GitHubAgentMatch(user_id=user_id, agent=cfg, trigger=resolved))
     return index
 
 
@@ -145,4 +145,4 @@ def lookup_agents(
     and the pre-resolved trigger config for this specific event, so the
     caller does not need to walk the agent's ``bindings`` again.
     """
-    return registry.get((repo, event), [])
+    return registry.get((repo.lower(), event), [])

backend/tests/test_github_dispatcher.py

@@ -47,6 +47,34 @@ async def _drain(bus: MessageBus) -> list[InboundMessage]:
     return out
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("configured_repo, payload_repo", [("Acme/Widget", "acme/widget"), ("acme/widget", "Acme/Widget")])
+async def test_fanout_matches_repository_case_insensitively(base_dir: Path, configured_repo: str, payload_repo: str) -> None:
+    """GitHub repository names identify the same repository regardless of case."""
+    _write_agent(
+        base_dir,
+        "default",
+        "reviewer",
+        {"name": "reviewer", "github": {"bindings": [{"repo": configured_repo, "triggers": {"issues": {"actions": ["opened"]}}}]}},
+    )
+    bus = MessageBus()
+    result = await fanout_event(
+        bus,
+        "issues",
+        "delivery-mixed-case",
+        {
+            "action": "opened",
+            "issue": {"number": 7, "user": {"login": "alice"}, "title": "Bug", "body": "Details"},
+            "repository": {"full_name": payload_repo},
+            "sender": {"login": "alice"},
+        },
+    )
+    assert result["fired_agents"] == ["reviewer"]
+    messages = await _drain(bus)
+    assert len(messages) == 1
+    assert messages[0].chat_id == payload_repo
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize("event, object_key", [("issues", "issue"), ("pull_request", "pull_request")])
 @pytest.mark.parametrize("author, sender, should_fire", [("owner", "other", False), ("other", "owner", True)])