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

pkg/pools/buffer.go

@@ -1,3 +1,6 @@
+// Package pools provides memory-efficient buffer and gzip reader pools
+// for reducing allocations in high-throughput request processing.
+// Buffers are automatically sized and recycled to minimize GC pressure.
 package pools
 
 import (
@@ -16,21 +19,21 @@ const (
 
 // bufferPool is the global pool for reusable buffers
 var bufferPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return bytes.NewBuffer(make([]byte, 0, InitialBufferSize))
 	},
 }
 
 // gzipWriterPool is the global pool for reusable gzip writers
 var gzipWriterPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return gzip.NewWriter(nil)
 	},
 }
 
 // gzipReaderPool is the global pool for reusable gzip readers
 var gzipReaderPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new(gzip.Reader)
 	},
 }