refactor: 引入 ScanSession，替代全局状态穿透扫描管道 (Phase 1-3)

- 新增 common/session.go: ScanSession 结构体封装 Config/State/Params/Dialer
- RunScan/Strategy/ExecuteScanTasks/executeScanTask 全部接收 session
- Plugin 接口从 Scan(ctx, info, config, state) 改为 Scan(ctx, info, session)
- 48 个插件实现统一更新签名
- Web API 构建 ScanSession 传给 RunScan
- CLI 模式通过 Initialize() 创建 session

core/scanner_test.go

@@ -215,7 +215,7 @@ type mockStrategy struct {
 	applicablePlugins map[string]bool // pluginName -> isApplicable
 }
 
-func (m *mockStrategy) Execute(_ context.Context, config *common.Config, state *common.State, info common.HostInfo, ch chan struct{}, wg *sync.WaitGroup) {
+func (m *mockStrategy) Execute(_ context.Context, session *common.ScanSession, info common.HostInfo, ch chan struct{}, wg *sync.WaitGroup) {
 }
 
 func (m *mockStrategy) GetPlugins() ([]string, bool) {