Harden health checks and refresh GitHub health cache

internal/checker/github_test.go

@@ -1,6 +1,7 @@
 package checker
 
 import (
+	"errors"
 	"testing"
 )
 
@@ -14,6 +15,10 @@ func TestExtractGitHubRepo(t *testing.T) {
 		{"https://github.com/docker/compose", "docker", "compose", true},
 		{"https://github.com/moby/moby", "moby", "moby", true},
 		{"https://github.com/user/repo/", "user", "repo", true},
+		{"https://github.com/user/repo?tab=readme-ov-file", "user", "repo", true},
+		{"https://github.com/user/repo#readme", "user", "repo", true},
+		{"https://github.com/user/repo.git", "user", "repo", true},
+		{"https://www.github.com/user/repo", "user", "repo", true},
 		{"https://github.com/user/repo/issues", "", "", false},
 		{"https://github.com/user/repo/wiki", "", "", false},
 		{"https://github.com/apps/dependabot", "", "", false},
@@ -52,3 +57,22 @@ func TestPartitionLinks(t *testing.T) {
 		t.Errorf("external links = %d, want 2", len(ext))
 	}
 }
+
+func TestIsGitHubAuthError(t *testing.T) {
+	tests := []struct {
+		err  error
+		want bool
+	}{
+		{errors.New("non-200 OK status code: 401 Unauthorized body: \"Bad credentials\""), true},
+		{errors.New("Resource not accessible by integration"), true},
+		{errors.New("dial tcp: lookup api.github.com: no such host"), false},
+		{errors.New("context deadline exceeded"), false},
+	}
+
+	for _, tt := range tests {
+		got := isGitHubAuthError(tt.err)
+		if got != tt.want {
+			t.Errorf("isGitHubAuthError(%q) = %v, want %v", tt.err, got, tt.want)
+		}
+	}
+}