Migrate logging to go-mana-component; delete logging/ package

Replaces the flat key-value logging scheme with component-based structured
logging via go-mana-component. Each layer (pool, worker, connection) builds
its own component identity and derives a *slog.Logger from a caller-supplied
slog.Handler.

- Delete logging/ package (logging.go, logging_test.go)
- Strip LoggingEnabled and LogLevel from ConnectionConfig, PoolConfig,
 WorkerConfig; remove associated option funcs
- Change NewConnection and NewConnectionFromSocket to accept ctx and
 slog.Handler instead of *slog.Logger; constructors build component
 identity via MustNew/MustExtend internally
- Change WorkerFactory, NewWorker, connect, and RunDialer to carry
 slog.Handler; remove PoolPlugin.Handler
- Change NewPool to establish pool component identity via MustNew;
 remove pool_id field, PoolPlugin.ID, and ErrInvalidPoolID
- Fix data race in MockSlogHandler: WithAttrs now shares parent mutex
 pointer rather than allocating a new one per child
- Run go fix

worker_start_test.go

@@ -65,11 +65,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {
@@ -91,11 +89,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {
@@ -144,11 +140,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {
@@ -184,11 +178,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {
@@ -230,11 +222,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {
@@ -278,11 +268,9 @@ func TestWorkerStart(t *testing.T) {
 		pool.Dialer = mockDialer(mockSocket)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			w.Start(pool)
-			wg.Done()
-		}()
+		})
 
 		honeybeetest.Eventually(t, func() bool {
 			select {