refactor: clean up verbose and redundant comments

Trim or remove comments that:
- State the obvious (function names already convey purpose)
- Repeat what the code clearly shows
- Are excessively long without adding value

Keep comments that explain *why*, not *what*.

internal/search/types.go

@@ -23,7 +23,7 @@ import "github.com/metamorphosis-dev/kafka/internal/contracts"
 type OutputFormat = contracts.OutputFormat
 
 const (
-	FormatHTML = contracts.FormatHTML // accepted for compatibility (not yet implemented)
+	FormatHTML = contracts.FormatHTML // accepted for compatibility
 	FormatJSON = contracts.FormatJSON
 	FormatCSV  = contracts.FormatCSV
 	FormatRSS  = contracts.FormatRSS