feat: add re-import from system buttons for Samba and NFS

Add 'Re-importar del sistema' buttons to the Samba and NFS pages,
mirroring the existing user import flow. Both buttons show a confirm
dialog before calling the respective /api/import/{samba,nfs} endpoints
which replace the DB table with the current system config.

Version bump: 0.6.0 → 0.6.1

Makefile

@@ -1,5 +1,5 @@
 BINARY=nasctl
-VERSION?=0.6.0
+VERSION?=0.6.1
 GO?=go
 LDFLAGS=-s -w -X github.com/darroyo/nasctl/internal/web.Version=$(VERSION) -X github.com/darroyo/nasctl/internal/web.Commit=$(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 BUILD_FLAGS=CGO_ENABLED=0