Shares of other services and RepoISO integration

- include SMB drop-ins from /etc/samba/smb.conf.d into the generated smb.conf
- keep smbd/nfs-server running while other services (/etc/exports.d, drop-ins) share,
  instead of disabling them when nasmon has no shares of its own
- list those shares read-only on /shares
- settings: RepoISO URL; poll its /api/integration/status, dashboard card, menu link,
  alerts for portal down, stale worker, failed jobs, unmounted publications

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/collect/repoiso.go

@@ -0,0 +1,54 @@
+package collect
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// RepoISO is the health summary of a RepoISO portal running on the same host
+// (GET <url>/api/integration/status). Reachable=false means the API did not answer.
+type RepoISO struct {
+	URL               string    `json:"url"`
+	Reachable         bool      `json:"reachable"`
+	Error             string    `json:"error,omitempty"`
+	CheckedAt         time.Time `json:"checked_at"`
+	Version           string    `json:"version"`
+	WorkerAlive       bool      `json:"worker_alive"`
+	WorkerHeartbeat   string    `json:"worker_heartbeat"`
+	Images            int       `json:"images"`
+	ImagesBytes       uint64    `json:"images_bytes"`
+	ImagesPending     int       `json:"images_pending"`
+	ImagesError       int       `json:"images_error"`
+	Publications      int       `json:"publications"`
+	PublicationsError int       `json:"publications_error"`
+	JobsActive        int       `json:"jobs_active"`
+	JobsFailed24h     int       `json:"jobs_failed_24h"`
+	Exports           int       `json:"exports"`
+}
+
+var repoisoClient = &http.Client{Timeout: 5 * time.Second}
+
+// FetchRepoISO queries the RepoISO status endpoint; errors are reported in the result.
+func FetchRepoISO(base string) RepoISO {
+	base = strings.TrimRight(base, "/")
+	r := RepoISO{URL: base, CheckedAt: time.Now()}
+	resp, err := repoisoClient.Get(base + "/api/integration/status")
+	if err != nil {
+		r.Error = err.Error()
+		return r
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		r.Error = fmt.Sprintf("HTTP %d", resp.StatusCode)
+		return r
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
+		r.Error = "bad response: " + err.Error()
+		return r
+	}
+	r.URL, r.Reachable, r.Error = base, true, ""
+	return r
+}