v0.9.0: Storage paths registry, per-app HDD_PATH resolution, storage management UI

- Fix backup toggles not appearing (read each app's own HDD_PATH from app.yaml)
- Storage paths registry in settings.json with auto-discovery from deployed apps
- Settings page "Adattárolók" section with disk usage, add/remove/default/schedulable
- Deploy page path field as dropdown of registered storage paths
- Health check storage monitoring (mount point, disk usage alerts)
- Mount-point validation utilities (Linux syscall + cross-platform stubs)
- Controller docker-compose mount changed to /mnt:/mnt:rw for multi-storage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/monitor/healthcheck.go

@@ -2,11 +2,13 @@ package monitor
 
 import (
 	"fmt"
+	"os"
 	"os/exec"
 	"strings"
 	"time"
 
 	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/system"
 )
 
@@ -20,13 +22,17 @@ type HealthReport struct {
 }
 
 // RunHealthCheck runs system checks and returns a diagnostic report.
-func RunHealthCheck(cfg *config.Config, cpuCollector *system.CPUCollector) *HealthReport {
+func RunHealthCheck(cfg *config.Config, cpuCollector *system.CPUCollector, storagePaths []settings.StoragePath) *HealthReport {
 	report := &HealthReport{
 		Status:    "ok",
 		Timestamp: time.Now(),
 	}
 
-	sysInfo := system.GetInfo(cfg.Paths.HDDPath, cpuCollector)
+	hddPath := cfg.Paths.HDDPath
+	if len(storagePaths) > 0 {
+		hddPath = storagePaths[0].Path
+	}
+	sysInfo := system.GetInfo(hddPath, cpuCollector)
 
 	// 1. Disk usage (SSD)
 	if sysInfo.DiskPercent > 0 {
@@ -88,6 +94,11 @@ func RunHealthCheck(cfg *config.Config, cpuCollector *system.CPUCollector) *Heal
 		report.Issues = append(report.Issues, fmt.Sprintf("Protected container not running: %s", name))
 	}
 
+	// 7. Storage paths
+	storageIssues, storageWarnings := checkStoragePaths(storagePaths)
+	report.Issues = append(report.Issues, storageIssues...)
+	report.Warnings = append(report.Warnings, storageWarnings...)
+
 	// Determine status
 	if len(report.Issues) > 0 {
 		report.Status = "fail"
@@ -158,3 +169,28 @@ func checkProtectedContainers(protected []string) []string {
 	}
 	return missing
 }
+
+func checkStoragePaths(paths []settings.StoragePath) (issues, warnings []string) {
+	for _, sp := range paths {
+		// Path accessible?
+		if _, err := os.Stat(sp.Path); err != nil {
+			warnings = append(warnings, fmt.Sprintf("Storage path not accessible: %s", sp.Path))
+			continue
+		}
+
+		// Mount point check
+		if !system.IsMountPoint(sp.Path) {
+			issues = append(issues, fmt.Sprintf("Storage path %s is NOT a mount point — data writes to SSD!", sp.Path))
+		}
+
+		// Disk usage
+		if di := system.GetDiskUsage(sp.Path); di != nil {
+			if di.UsedPercent >= 95 {
+				issues = append(issues, fmt.Sprintf("Storage %s nearly full: %.0f%%", sp.Path, di.UsedPercent))
+			} else if di.UsedPercent >= 90 {
+				warnings = append(warnings, fmt.Sprintf("Storage %s usage high: %.0f%%", sp.Path, di.UsedPercent))
+			}
+		}
+	}
+	return
+}