(chore): document and test new LogLevel APIs

- add godoc for SameLevel and Equal
- update package docs and READMEs with new helpers
- refresh unreleased release notes
- add tests for Printf, HTTP method levels, and level constructors

doc.go

@@ -17,6 +17,11 @@
 // passed to writers. Call SetFormatter on a writer to customize timestamps,
 // traceback fields, colors, and message layout.
 //
+// The package also provides helper constructors for common severities such as
+// NewInfoLogLevel and NewErrorLogLevel, plus predefined HTTP method-specific
+// levels such as HTTPGetLevel and HTTPPostLevel. Use LogLevelForMethod to map
+// an HTTP method to one of those predefined levels.
+//
 // Basic usage:
 //
 //	logger := sneklog.CreateLogger().
@@ -41,4 +46,7 @@
 // the logger and are closed by Logger.Close. Writers created from existing
 // io.Writer values through CreateTextWriter or CreateJsonWriter remain owned by
 // the caller and are not closed by the logger.
+//
+// LogLevel values can be compared with SameLevel when only severity matters or
+// with Equal when the full level configuration must match.
 package sneklog