refactor(cmd): split molecule.go into focused files

Split the 1929-line molecule.go into 5 focused files:
- molecule.go (376): command definitions, init(), loadMoleculeCatalog
- molecule_status.go (673): status, progress, current commands
- molecule_list.go (432): list, show, export, parse, instances
- molecule_lifecycle.go (359): instantiate, catalog, burn, squash
- molecule_attach.go (128): attach, detach, attachment

No functional changes - pure refactoring for maintainability.

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

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

internal/cmd/molecule_attach.go

@@ -0,0 +1,128 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+	"github.com/steveyegge/gastown/internal/beads"
+	"github.com/steveyegge/gastown/internal/style"
+)
+
+func runMoleculeAttach(cmd *cobra.Command, args []string) error {
+	pinnedBeadID := args[0]
+	moleculeID := args[1]
+
+	workDir, err := findLocalBeadsDir()
+	if err != nil {
+		return fmt.Errorf("not in a beads workspace: %w", err)
+	}
+
+	b := beads.New(workDir)
+
+	// Attach the molecule
+	issue, err := b.AttachMolecule(pinnedBeadID, moleculeID)
+	if err != nil {
+		return fmt.Errorf("attaching molecule: %w", err)
+	}
+
+	attachment := beads.ParseAttachmentFields(issue)
+	fmt.Printf("%s Attached %s to %s\n", style.Bold.Render("✓"), moleculeID, pinnedBeadID)
+	if attachment != nil && attachment.AttachedAt != "" {
+		fmt.Printf("  attached_at: %s\n", attachment.AttachedAt)
+	}
+
+	return nil
+}
+
+func runMoleculeDetach(cmd *cobra.Command, args []string) error {
+	pinnedBeadID := args[0]
+
+	workDir, err := findLocalBeadsDir()
+	if err != nil {
+		return fmt.Errorf("not in a beads workspace: %w", err)
+	}
+
+	b := beads.New(workDir)
+
+	// Check current attachment first
+	attachment, err := b.GetAttachment(pinnedBeadID)
+	if err != nil {
+		return fmt.Errorf("checking attachment: %w", err)
+	}
+
+	if attachment == nil {
+		fmt.Printf("%s No molecule attached to %s\n", style.Dim.Render("ℹ"), pinnedBeadID)
+		return nil
+	}
+
+	previousMolecule := attachment.AttachedMolecule
+
+	// Detach the molecule
+	_, err = b.DetachMolecule(pinnedBeadID)
+	if err != nil {
+		return fmt.Errorf("detaching molecule: %w", err)
+	}
+
+	fmt.Printf("%s Detached %s from %s\n", style.Bold.Render("✓"), previousMolecule, pinnedBeadID)
+
+	return nil
+}
+
+func runMoleculeAttachment(cmd *cobra.Command, args []string) error {
+	pinnedBeadID := args[0]
+
+	workDir, err := findLocalBeadsDir()
+	if err != nil {
+		return fmt.Errorf("not in a beads workspace: %w", err)
+	}
+
+	b := beads.New(workDir)
+
+	// Get the issue
+	issue, err := b.Show(pinnedBeadID)
+	if err != nil {
+		return fmt.Errorf("getting issue: %w", err)
+	}
+
+	attachment := beads.ParseAttachmentFields(issue)
+
+	if moleculeJSON {
+		type attachmentOutput struct {
+			IssueID          string `json:"issue_id"`
+			IssueTitle       string `json:"issue_title"`
+			Status           string `json:"status"`
+			AttachedMolecule string `json:"attached_molecule,omitempty"`
+			AttachedAt       string `json:"attached_at,omitempty"`
+		}
+		out := attachmentOutput{
+			IssueID:    issue.ID,
+			IssueTitle: issue.Title,
+			Status:     issue.Status,
+		}
+		if attachment != nil {
+			out.AttachedMolecule = attachment.AttachedMolecule
+			out.AttachedAt = attachment.AttachedAt
+		}
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		return enc.Encode(out)
+	}
+
+	// Human-readable output
+	fmt.Printf("\n%s: %s\n", style.Bold.Render(issue.ID), issue.Title)
+	fmt.Printf("Status: %s\n", issue.Status)
+
+	if attachment == nil || attachment.AttachedMolecule == "" {
+		fmt.Printf("\n%s\n", style.Dim.Render("No molecule attached"))
+	} else {
+		fmt.Printf("\n%s\n", style.Bold.Render("Attached Molecule:"))
+		fmt.Printf("  ID: %s\n", attachment.AttachedMolecule)
+		if attachment.AttachedAt != "" {
+			fmt.Printf("  Attached at: %s\n", attachment.AttachedAt)
+		}
+	}
+
+	return nil
+}