Consolidate CLI verbs; retire overlapping commands

The verb surface accumulated overlapping cleanup commands. Consolidate
so each cleanup verb has one meaning:

- Rename 'database purge' -> 'database delete'. The command removes the
  SQLite file entirely; "purge" wrongly suggested purging contents.
- Fold 'snapshot cleanup' into 'prune'. Prune now runs three passes:
  reconcile local snapshots against the remote (previously the
  standalone cleanup command), drop orphaned local rows, then delete
  unreferenced remote blobs. One command, one mental model.
- Delete 'store info'. Its output was a strict subset of 'remote info',
  which already prints storage type + location. Any user reaching for
  either should reach for 'remote info'.
- Drop 'snapshot remove --all'. It duplicated 'remote nuke --force'.
  'remote nuke' is the single supported entry point for wiping the
  destination store.

Also update the storage-binding error message to reference the new
'vaultik database delete' name.

internal/cli/entry_test.go

@@ -18,7 +18,7 @@ func TestCLIEntry(t *testing.T) {
 	}
 
 	// Verify all subcommands are registered
-	expectedCommands := []string{"config", "snapshot", "store", "prune", "info", "version", "remote", "database"}
+	expectedCommands := []string{"config", "snapshot", "prune", "info", "version", "remote", "database"}
 	for _, expected := range expectedCommands {
 		found := false
 		for _, cmd := range cmd.Commands() {
@@ -38,7 +38,7 @@ func TestCLIEntry(t *testing.T) {
 		t.Errorf("Failed to find snapshot command: %v", err)
 	} else {
 		// Check snapshot subcommands
-		expectedSubCommands := []string{"create", "list", "purge", "verify", "cleanup", "restore"}
+		expectedSubCommands := []string{"create", "list", "purge", "verify", "remove", "restore"}
 		for _, expected := range expectedSubCommands {
 			found := false
 			for _, subcmd := range snapshotCmd.Commands() {