refactor: remove legacy .beads-wisp infrastructure (gt-5klh)

Wisps are now just a flag on regular beads issues (Wisp=true).
No separate directory needed - hooks stored in .beads/.

Changes:
- wisp package: WispDir now points to .beads/, removed PatrolCycle
- manager.go: removed initWispBeads() - no separate dir to create
- mrqueue.go: MRs stored in .beads/mq/ instead of .beads-wisp/mq/
- doctor: removed obsolete wisp directory checks
- docs: updated wisp-architecture.md to reflect simplified model

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

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

internal/cmd/doctor.go

@@ -71,13 +71,6 @@ func runDoctor(cmd *cobra.Command, args []string) error {
 	d.Register(doctor.NewLinkedPaneCheck())
 	d.Register(doctor.NewThemeCheck())
 
-	// Wisp storage checks
-	d.Register(doctor.NewWispExistsCheck())
-	d.Register(doctor.NewWispGitCheck())
-	d.Register(doctor.NewWispOrphansCheck())
-	d.Register(doctor.NewWispSizeCheck())
-	d.Register(doctor.NewWispStaleCheck())
-
 	// Patrol system checks
 	d.Register(doctor.NewPatrolMoleculesExistCheck())
 	d.Register(doctor.NewPatrolHooksWiredCheck())