fix: bug fixes, test coverage, and CI workflow

- Fix Nodes.First() panic on empty slice (return nil)
- Fix ticker leak in archive.go (create once, defer Stop)
- Fix cookie path matching for empty and root paths
- Fix lost query params in google.go (u.Query().Set was discarded)
- Fix type assertion panic in useragents.go
- Fix dropped date parse error in powerball.go
- Remove unreachable dead code in megamillions.go and powerball.go
- Simplify document.go WaitForNetworkIdle, remove unused root field
- Remove debug fmt.Println calls across codebase
- Replace panic(err) with stderr+exit in all cmd/ programs
- Fix duckduckgo cmd: remove useless defer, return error on bad safesearch
- Fix archive cmd: ToConfig returns error instead of panicking
- Add 39+ unit tests across 6 new test files
- Add Gitea Actions CI workflow (build, test, vet in parallel)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sites/useragents/cmd/useragents.go

@@ -49,10 +49,8 @@ func main() {
 		},
 	}
 
-	err := cli.Run(context.Background(), os.Args)
-
-	if err != nil {
-		panic(err)
+	if err := cli.Run(context.Background(), os.Args); err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
 	}
-
 }

sites/useragents/useragents.go

@@ -44,8 +44,6 @@ func (c Config) GetMostCommonDesktopUserAgent(ctx context.Context, b extractor.B
 	}
 	data := []map[string]any{}
 
-	fmt.Println("text", text)
-
 	err = json.Unmarshal([]byte(text), &data)
 
 	if err != nil {
@@ -63,8 +61,12 @@ func (c Config) GetMostCommonDesktopUserAgent(ctx context.Context, b extractor.B
 		}
 
 		if pct > highestPct {
+			ua, ok := agent["ua"].(string)
+			if !ok {
+				continue
+			}
 			highestPct = pct
-			highestAgent = agent["ua"].(string)
+			highestAgent = ua
 		}
 	}