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/nodb.go

@@ -72,8 +72,11 @@ func initializeNoDbMode() error {
 
 	debug.Logf("using prefix '%s'", prefix)
 
-	// Set global store
+	// Set global store and mark as active (fixes bd comment --no-db)
+	storeMutex.Lock()
 	store = memStore
+	storeActive = true
+	storeMutex.Unlock()
 	return nil
 }
 
@@ -218,7 +221,7 @@ func writeIssuesToJSONL(memStore *memory.MemoryStorage, beadsDir string) error {
 	// Wisps exist only in SQLite and are shared via .beads/redirect, not JSONL.
 	filtered := make([]*types.Issue, 0, len(issues))
 	for _, issue := range issues {
-		if !issue.Wisp {
+		if !issue.Ephemeral {
 			filtered = append(filtered, issue)
 		}
 	}