fix(daemon): allow read-only daemon commands with Dolt backend

The daemon guard was blocking ALL daemon commands when using Dolt
backend, including read-only commands like `status`, `stop`, `logs`.

Changes:
- Rename guard to `guardDaemonStartForDolt` (more accurate)
- Remove `PersistentPreRunE` from `daemonCmd` and `daemonsCmd`
- Add `PreRunE` guard only to `daemonStartCmd` and `daemonsRestartCmd`
- Update test to use new function name and test start command

Now:
- `bd daemon status` works with Dolt backend
- `bd daemon start` blocked unless `--federation` flag
- `bd daemon start --federation` works (starts dolt sql-server)

Fixes: bd-n7o47

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

cmd/bd/daemons.go

@@ -79,7 +79,6 @@ Subcommands:
   logs    - View daemon logs
   killall - Stop all running daemons
   restart - Restart a specific daemon (not yet implemented)`,
-	PersistentPreRunE: guardDaemonUnsupportedForDolt,
 }
 var daemonsListCmd = &cobra.Command{
 	Use:   "list",
@@ -225,7 +224,8 @@ var daemonsRestartCmd = &cobra.Command{
 	Short: "Restart a specific bd daemon",
 	Long: `Restart a specific bd daemon by workspace path or PID.
 Stops the daemon gracefully, then starts a new one.`,
-	Args: cobra.ExactArgs(1),
+	Args:    cobra.ExactArgs(1),
+	PreRunE: guardDaemonStartForDolt,
 	Run: func(cmd *cobra.Command, args []string) {
 		target := args[0]
 		searchRoots, _ := cmd.Flags().GetStringSlice("search")