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

circuit_breaker_test.go

@@ -193,7 +193,7 @@ func (suite *CircuitBreakerTestSuite) TestExecuteFunctionBehavior() {
 
 	// Test with success
 	result := "success"
-	execResult, err := cb.Execute(func() (interface{}, error) {
+	execResult, err := cb.Execute(func() (any, error) {
 		return result, nil
 	})
 
@@ -202,7 +202,7 @@ func (suite *CircuitBreakerTestSuite) TestExecuteFunctionBehavior() {
 
 	// Test with error
 	testErr := errors.New("test error")
-	_, err = cb.Execute(func() (interface{}, error) {
+	_, err = cb.Execute(func() (any, error) {
 		return nil, testErr
 	})