refactor: rename ephemeral to wisp (beads v0.33.1 terminology)

Update .beads-ephemeral/ to .beads-wisp/ per beads v0.33.1:
- Renamed initEphemeralBeads to initWispBeads
- Changed directory from .beads-ephemeral/ to .beads-wisp/
- Changed config from ephemeral: true to wisp: true
- Updated help text and output messages
- Updated tests

Generated with Claude Code

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

internal/cmd/rig.go

@@ -43,7 +43,7 @@ var rigAddCmd = &cobra.Command{
 This creates a rig container with:
   - config.json           Rig configuration
   - .beads/               Rig-level issue tracking (initialized)
-  - .beads-ephemeral/     Local runtime tracking (gitignored)
+  - .beads-wisp/          Local wisp/molecule tracking (gitignored)
   - refinery/rig/         Canonical main clone
   - mayor/rig/            Mayor's working clone
   - crew/main/            Default human workspace
@@ -193,7 +193,7 @@ func runRigAdd(cmd *cobra.Command, args []string) error {
 	fmt.Printf("  %s/\n", name)
 	fmt.Printf("  ├── config.json\n")
 	fmt.Printf("  ├── .beads/           (prefix: %s)\n", newRig.Config.Prefix)
-	fmt.Printf("  ├── .beads-ephemeral/ (local runtime tracking)\n")
+	fmt.Printf("  ├── .beads-wisp/      (local wisp/molecule tracking)\n")
 	fmt.Printf("  ├── refinery/rig/     (canonical main)\n")
 	fmt.Printf("  ├── mayor/rig/        (mayor's clone)\n")
 	fmt.Printf("  ├── crew/%s/        (your workspace)\n", rigAddCrew)