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

transport/connection_goroutine_test.go

@@ -1,6 +1,7 @@
 package transport
 
 import (
+	"context"
 	"git.wisehodl.dev/jay/go-honeybee/honeybeetest"
 	"github.com/gorilla/websocket"
 	"github.com/stretchr/testify/assert"
@@ -66,7 +67,7 @@ func TestStartReader(t *testing.T) {
 			return 0, nil, io.EOF
 		}
 
-		conn, err := NewConnectionFromSocket(mockSocket, nil, nil)
+		conn, err := NewConnectionFromSocket(context.Background(), mockSocket, nil, nil)
 		assert.NoError(t, err)
 
 		honeybeetest.Eventually(t, func() bool {