Pull auto-inits repo, restores files, and add -r global shorthand.

pull now works on a fresh machine: inits ~/.sgard if missing, always
pulls when local manifest is empty, and restores all files after
downloading blobs. -r is now a global shorthand for --remote; list
uses resolveRemoteConfig() like prune.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/client.go

@@ -206,8 +206,8 @@ func (c *Client) doPull(ctx context.Context, g *garden.Garden) (int, error) {
 	serverManifest := server.ProtoToManifest(pullResp.GetManifest())
 	localManifest := g.GetManifest()
 
-	// If local is newer or equal, nothing to do.
-	if !serverManifest.Updated.After(localManifest.Updated) {
+	// If local has files and is newer or equal, nothing to do.
+	if len(localManifest.Files) > 0 && !serverManifest.Updated.After(localManifest.Updated) {
 		return 0, nil
 	}