refactor: remove unused bd pin/unpin/hook commands (bd-x0zl)

Analysis found these commands are dead code:
- gt never calls `bd pin` - uses `bd update --status=pinned` instead
- Beads.Pin() wrapper exists but is never called
- bd hook functionality duplicated by gt mol status
- Code comment says "pinned field is cosmetic for bd hook visibility"

Removed:
- cmd/bd/pin.go
- cmd/bd/unpin.go
- cmd/bd/hook.go

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/bd/delete_rpc_test.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"strings"
@@ -897,11 +898,7 @@ func setupDaemonTestEnvForDelete(t *testing.T) (context.Context, context.CancelF
 
 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 
-	log := daemonLogger{
-		logFunc: func(format string, args ...interface{}) {
-			t.Logf("[daemon] "+format, args...)
-		},
-	}
+	log := daemonLogger{logger: slog.New(slog.NewTextHandler(io.Discard, &slog.HandlerOptions{Level: slog.LevelInfo}))}
 
 	server, _, err := startRPCServer(ctx, socketPath, testStore, tmpDir, testDBPath, log)
 	if err != nil {