chore(security,refactor): extract sanitization and improve code quality (#41)

* chore(security,refactor): extract sanitization and improve code quality

- [x] Extract sanitization functions to dedicated sanitization.go module
- [x] Add comprehensive golangci-lint v2 configuration with security rules
- [x] Replace interface{} with any type throughout codebase
- [x] Add admin API authentication security warning
- [x] Extract WebSocket and stats streaming constants
- [x] Add best-effort error handling comments for resource cleanup
- [x] Expand sensitive field patterns for improved PII redaction
- [x] Simplify safety checks and remove redundant nil validations
- [x] Improve test coverage for password field redaction patterns

* refactor: replace interface{} with any type alias

- [x] Replace all `map[string]interface{}` with `map[string]any`
- [x] Replace all `interface{}` with `any` in function signatures and type definitions
- [x] Update sync.Pool New function returns from `interface{}` to `any`
- [x] Add package documentation comments to 8 package files
- [x] Update type assertions and casts to work with `any` type

logging/logger.go

@@ -1,3 +1,6 @@
+// Package libpack_logger provides structured JSON logging with configurable
+// log levels, caller information, and automatic sensitive data redaction.
+// Supports debug, info, warning, and error log levels.
 package libpack_logger
 
 import (
@@ -47,13 +50,13 @@ type Logger struct {
 
 // LogMessage represents a log message with optional pairs.
 type LogMessage struct {
-	Pairs   map[string]interface{}
+	Pairs   map[string]any
 	Message string
 }
 
 // bufferPool is used to reuse bytes.Buffer for efficiency.
 var bufferPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new(bytes.Buffer)
 	},
 }
@@ -132,7 +135,7 @@ func (l *Logger) shouldLog(level int) bool {
 // log writes the log message with the given level.
 func (l *Logger) log(level int, m *LogMessage) {
 	if m.Pairs == nil {
-		m.Pairs = make(map[string]interface{})
+		m.Pairs = make(map[string]any)
 	}
 
 	m.Pairs[fieldNames["timestamp"]] = time.Now().Format(l.timeFormat)

logging/logger_race_test.go

@@ -24,7 +24,7 @@ func TestLogConcurrentAccess(t *testing.T) {
 			defer wg.Done()
 			msg := &LogMessage{
 				Message: "concurrent log test",
-				Pairs: map[string]interface{}{
+				Pairs: map[string]any{
 					"goroutine_id": id,
 				},
 			}