fix(crew): infer rig from cwd for 'gt crew start --all'

The crew start command now infers the rig name from the current
working directory when using --all without specifying a rig. This
matches the behavior of crew stop and other commands.

Before: gt crew start gastown --all (required)
After:  gt crew start --all (infers from cwd)

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

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

internal/cmd/crew.go

@@ -240,27 +240,30 @@ var crewPrevCmd = &cobra.Command{
 }
 
 var crewStartCmd = &cobra.Command{
-	Use:     "start <rig> [name]",
+	Use:     "start [rig] [name...]",
 	Aliases: []string{"spawn"},
 	Short:   "Start crew worker(s) in a rig",
 	Long: `Start crew workers in a rig, creating workspaces if they don't exist.
 
-Takes the rig name as the first argument. Optionally specify a crew member name
-to start just that worker, or use --all to start all crew members in the rig.
+The rig name can be provided as the first argument, or inferred from the
+current directory. Optionally specify crew member names to start specific
+workers, or use --all to start all crew members in the rig.
 
 The crew session starts in the background with Claude running and ready.
 
 Examples:
   gt crew start gastown joe       # Start joe in gastown rig
   gt crew start gastown --all     # Start all crew in gastown rig
-  gt crew start beads             # Error: specify name or --all
+  gt crew start --all             # Start all crew (rig inferred from cwd)
   gt crew start beads grip fang   # Start grip and fang in beads rig`,
 	Args: func(cmd *cobra.Command, args []string) error {
-		if len(args) < 1 {
-			return fmt.Errorf("requires at least 1 argument: the rig name")
+		// With --all, we can have 0 args (infer rig) or 1+ args (rig specified)
+		if crewAll {
+			return nil
 		}
-		if len(args) == 1 && !crewAll {
-			return fmt.Errorf("specify a crew member name or use --all to start all crew in the rig")
+		// Without --all, need at least rig and one crew name
+		if len(args) < 2 {
+			return fmt.Errorf("requires rig and crew name, or use --all")
 		}
 		return nil
 	},

internal/cmd/crew_lifecycle.go

@@ -219,17 +219,27 @@ func runCrewRefresh(cmd *cobra.Command, args []string) error {
 }
 
 // runCrewStart starts crew workers in a rig.
-// args[0] is the rig name (required)
+// args[0] is the rig name (optional if inferrable from cwd)
 // args[1:] are crew member names (optional, or use --all flag)
 func runCrewStart(cmd *cobra.Command, args []string) error {
-	rigName := args[0]
-	crewNames := args[1:]
+	var rigName string
+	var crewNames []string
 
-	// Get the rig manager and rig
+	if len(args) == 0 {
+		// No args - infer rig from cwd (only valid with --all)
+		rigName = "" // getCrewManager will infer from cwd
+	} else {
+		rigName = args[0]
+		crewNames = args[1:]
+	}
+
+	// Get the rig manager and rig (infers from cwd if rigName is empty)
 	crewMgr, r, err := getCrewManager(rigName)
 	if err != nil {
 		return err
 	}
+	// Update rigName in case it was inferred
+	rigName = r.Name
 
 	// If --all flag, get all crew members
 	if crewAll {