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/contracts/types.go

@@ -20,18 +20,15 @@ package contracts
 type OutputFormat string
 
 const (
-	FormatHTML OutputFormat = "html" // accepted for compatibility (not yet implemented)
+	FormatHTML OutputFormat = "html" // accepted for compatibility
 	FormatJSON OutputFormat = "json"
 	FormatCSV  OutputFormat = "csv"
 	FormatRSS  OutputFormat = "rss"
 )
 
 type SearchRequest struct {
-	// Format is what the client requested via `format=...`.
-	Format OutputFormat
-
-	Query string
-
+	Format     OutputFormat
+	Query      string
 	Pageno     int
 	Safesearch int
 	TimeRange  *string
@@ -39,16 +36,14 @@ type SearchRequest struct {
 	TimeoutLimit *float64
 	Language     string
 
-	// Engines and categories are used for deciding which engines run locally vs are proxied.
-	// For now, engines can be supplied directly via the `engines` form parameter.
+	// Engines and categories decide which engines run locally vs proxy to upstream.
 	Engines    []string
 	Categories []string
 
 	// EngineData matches the `engine_data-<engine>-<key>=<value>` parameters.
 	EngineData map[string]map[string]string
 
-	// AccessToken is an optional request token used to gate paid/limited engines.
-	// It is not part of the upstream JSON schema; it only influences local engines.
+	// AccessToken gates paid/limited engines. Not part of upstream JSON schema.
 	AccessToken string
 }