v0.24.0 — Pre-testing observability: debug logging, diagnostic dump, startup self-test

- Add [DEBUG] logging across all modules (backup, storage, sync, selfupdate,
  monitor, notify, report, assets, setup) gated behind logging.level: "debug"
- Add /api/debug/dump endpoint returning full controller state JSON (debug only)
- Add startup self-test validating 9 subsystems (Docker, dirs, storage, hub,
  restic repos, metrics DB) with pass/warn/fail summary
- New packages: internal/selftest, internal/util
- Constructor/signature changes: debug bool params, logger params on
  RunHealthCheck and BuildReport, smart watchdog probe logging

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

controller/internal/storage/scan_linux.go

@@ -5,11 +5,14 @@ package storage
 import (
 	"encoding/json"
 	"fmt"
+	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
+
+	"gitea.dooplex.hu/admin/felhom-controller/internal/util"
 )
 
 // lsblkOutput matches the top-level JSON from lsblk -J.
@@ -193,7 +196,13 @@ func partitionToParentDisk(devPath string) string {
 // enrichWithBlkid fills in missing FSType, UUID, and Label on partitions using blkid.
 // Probes each partition individually via /host-dev (Docker overrides /dev with its own
 // tmpfs, so the host block devices are accessible at /host-dev instead).
-func enrichWithBlkid(disks []BlockDevice) {
+func enrichWithBlkid(disks []BlockDevice, logger *log.Logger, debug bool) {
+	dbg := func(format string, args ...interface{}) {
+		if debug && logger != nil {
+			logger.Printf("[DEBUG] enrichWithBlkid: "+format, args...)
+		}
+	}
+
 	for i := range disks {
 		for j := range disks[i].Partitions {
 			p := &disks[i].Partitions[j]
@@ -202,16 +211,25 @@ func enrichWithBlkid(disks []BlockDevice) {
 			if p.FSType == "" {
 				if out, err := exec.Command("blkid", "-o", "value", "-s", "TYPE", hostPath).Output(); err == nil {
 					p.FSType = strings.TrimSpace(string(out))
+					dbg("blkid TYPE %s → %q", hostPath, p.FSType)
+				} else {
+					dbg("blkid TYPE %s failed: %v", hostPath, err)
 				}
 			}
 			if p.UUID == "" {
 				if out, err := exec.Command("blkid", "-o", "value", "-s", "UUID", hostPath).Output(); err == nil {
 					p.UUID = strings.TrimSpace(string(out))
+					dbg("blkid UUID %s → %q", hostPath, p.UUID)
+				} else {
+					dbg("blkid UUID %s failed: %v", hostPath, err)
 				}
 			}
 			if p.Label == "" {
 				if out, err := exec.Command("blkid", "-o", "value", "-s", "LABEL", hostPath).Output(); err == nil {
 					p.Label = strings.TrimSpace(string(out))
+					dbg("blkid LABEL %s → %q", hostPath, p.Label)
+				} else {
+					dbg("blkid LABEL %s failed: %v", hostPath, err)
 				}
 			}
 		}
@@ -220,7 +238,13 @@ func enrichWithBlkid(disks []BlockDevice) {
 
 // ScanDisks detects all block devices and classifies them into
 // available (not mounted, not system) and system/mounted disks.
-func ScanDisks() (*ScanResult, error) {
+func ScanDisks(logger *log.Logger, debug bool) (*ScanResult, error) {
+	dbg := func(format string, args ...interface{}) {
+		if debug && logger != nil {
+			logger.Printf("[DEBUG] ScanDisks: "+format, args...)
+		}
+	}
+
 	out, err := exec.Command(
 		"lsblk", "-J", "-b",
 		"-o", "NAME,PATH,SIZE,TYPE,FSTYPE,MOUNTPOINT,MODEL,RM",
@@ -229,11 +253,15 @@ func ScanDisks() (*ScanResult, error) {
 		return nil, fmt.Errorf("lsblk failed: %w", err)
 	}
 
+	dbg("raw lsblk JSON: %s", util.TruncateStr(string(out), 500))
+
 	var parsed lsblkOutput
 	if err := json.Unmarshal(out, &parsed); err != nil {
 		return nil, fmt.Errorf("lsblk JSON parse failed: %w", err)
 	}
 
+	dbg("lsblk returned %d block devices", len(parsed.BlockDevices))
+
 	// Get system disk names from host fstab (works correctly inside container)
 	systemDiskNames := getSystemDiskNames()
 
@@ -287,16 +315,27 @@ func ScanDisks() (*ScanResult, error) {
 		isSystem := systemDiskNames[dev.Name]
 		bd.Mounted = anyMounted || isSystem
 
+		classification := "available"
 		if isSystem || anyMounted {
+			classification = "system"
 			result.SystemDisks = append(result.SystemDisks, bd)
 		} else {
 			result.AvailableDisks = append(result.AvailableDisks, bd)
 		}
+
+		dbg("disk %s: model=%q size=%s partitions=%d removable=%v classification=%s",
+			bd.Name, bd.Model, bd.Size, len(bd.Partitions), bd.Removable, classification)
+
+		for _, p := range bd.Partitions {
+			dbg("  partition %s: fstype=%q mountpoint=%q size=%s", p.Name, p.FSType, p.MountPoint, p.Size)
+		}
 	}
 
+	dbg("classification result: %d available, %d system", len(result.AvailableDisks), len(result.SystemDisks))
+
 	// Enrich FSType, UUID, Label from blkid (lsblk can't probe fstype in container)
-	enrichWithBlkid(result.AvailableDisks)
-	enrichWithBlkid(result.SystemDisks)
+	enrichWithBlkid(result.AvailableDisks, logger, debug)
+	enrichWithBlkid(result.SystemDisks, logger, debug)
 
 	return result, nil
 }