release: v2.4.1 - bug fixes, refactoring, CI updates

- Bump VERSION to 2.4.1
- Add CHANGELOG entry for v2.4.1
- Update Go version in CI/Release workflows: 1.21 -> 1.24
- Update build.ps1 version: 2.2.2 -> 2.4.1

Author: lordixir

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: '1.24'
           cache: true
 
       - name: Install dependencies
@@ -40,7 +40,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: '1.24'
           cache: true
 
       - name: golangci-lint
@@ -76,7 +76,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: '1.24'
           cache: true
 
       - name: Build

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: '1.24'
           cache: true
 
       - name: Run tests

CHANGELOG.md

@@ -2,6 +2,23 @@
 
 All notable changes to this project will be documented in this file.
 
+## [2.4.1] - 2026-02-25
+
+### Fixed
+- **Data Race**: `Cache.Save()` used `RLock` for write operation → fixed to `Lock`
+- **Thread Safety**: Interrupt handler accessed `Websites` field directly → now uses `GetWebsites()`
+- **Case Sensitivity**: Domain title comparison now uses `strings.EqualFold` for case-insensitive matching
+- **Duplicate Save**: `MarkCompleted()+Save()` was called twice → reduced to single call in `printOnce.Do`
+- **Unused Variable**: `GenerateCacheFileName` computed `timestamp` even when unused
+
+### Improved
+- **Code Deduplication**: `ResolveSite` + `ResolveSiteWithCache` refactored into shared `runScan()` (448→306 lines)
+- **Concurrency**: `InterruptData` upgraded from `sync.Mutex` to `sync.RWMutex` with `RLock` for reads
+- **Cache Progress**: `GetProgress()` now returns estimated total IP count instead of 0
+- **Dead Code**: Removed unused `Websites` parameter from `ResolveSite`/`ResolveSiteWithCache` and callers
+
+---
+
 ## [2.4.0] - 2026-02-22
 
 ### Added

VERSION

@@ -1 +1 @@
-2.4.0
+2.4.1

build.ps1

@@ -1,7 +1,7 @@
 # ipmap Multi-Platform Build Script
 # Builds for macOS (ARM64 + AMD64) and Linux (AMD64)
 
-$VERSION = "2.2.2"
+$VERSION = "2.4.1"
 $APP_NAME = "ipmap"
 $BUILD_DIR = "bin"