Remediate all lint findings under the canonical golangci-lint config

Fix every finding surfaced by the canonical .golangci.yml with
golangci-lint v2.12.2 (refs #61), behavior-preserving throughout:

- err113: dynamic errors replaced with package-level sentinels and %w
  wrapping; direct comparisons converted to errors.Is
- goprintffuncname: printf-style helpers renamed with an f suffix
  (ui.Writer message methods, cli.ReportErrorf, database.Fatalf,
  vaultik stdoutf) and all call sites updated
- revive: stuttering type names renamed (blob.Handler, blob.WithReader,
  blob.ChunkPosition, storage.URL, storage.Info), doc comments added,
  unused parameters blanked, package comments added
- contextcheck/noctx: ctx threaded through blob.Packer
  (AddChunk/Flush/FinalizeBlob/PackChunks) and scanner call sites;
  context-aware exec and sql variants used
- funlen/cyclop/gocognit/nestif/dupl: oversized or duplicated
  functions split into focused helpers across production and test code
- paralleltest/tparallel/thelper/usetesting/testpackage: tests
  parallelized where safe (global log.Initialize kept in the serial
  phase), helpers marked, t.TempDir adopted, external test packages
  where only exported API is used
- gosec: integer conversions clamped or justified, header timeouts
  added, remaining findings suppressed with per-site justifications
- mnd/goconst/lll/wsl_v5/nlreturn/noinlineerr/errcheck and other
  mechanical findings fixed directly

Remove the deprecated log.LogOptions alias (callers migrated to
log.Options). make check is green.

internal/cli/snapshot_restore.go

@@ -14,6 +14,10 @@ import (
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )
 
+// restoreMinArgs is the minimum positional argument count of
+// `snapshot restore <snapshot-id> <target-dir> [paths...]`.
+const restoreMinArgs = 2
+
 // RestoreOptions contains options for the restore command
 type RestoreOptions struct {
 	TargetDir string
@@ -39,31 +43,36 @@ func newSnapshotRestoreCommand() *cobra.Command {
 		Short: "Restore files from a snapshot",
 		Long: `Download and decrypt files from a backup snapshot.
 
-This command will restore files from the specified snapshot to the target directory.
+This command will restore files from the specified snapshot to the
+target directory.
 If no paths are specified, all files are restored.
 If paths are specified, only matching files/directories are restored.
 
-Requires the VAULTIK_AGE_SECRET_KEY environment variable to be set with the age private key.
+Requires the VAULTIK_AGE_SECRET_KEY environment variable to be set with
+the age private key.
 
 Examples:
   # Restore entire snapshot
   vaultik snapshot restore myhost_docs_2025-01-01T12:00:00Z /restore
 
   # Restore specific file
-  vaultik snapshot restore myhost_docs_2025-01-01T12:00:00Z /restore /home/user/important.txt
+  vaultik snapshot restore myhost_docs_2025-01-01T12:00:00Z /restore \
+    /home/user/important.txt
 
   # Restore specific directory
-  vaultik snapshot restore myhost_docs_2025-01-01T12:00:00Z /restore /home/user/documents/
+  vaultik snapshot restore myhost_docs_2025-01-01T12:00:00Z /restore \
+    /home/user/documents/
 
   # Restore and verify all files
   vaultik snapshot restore --verify myhost_docs_2025-01-01T12:00:00Z /restore`,
-		Args: cobra.MinimumNArgs(2),
+		Args: cobra.MinimumNArgs(restoreMinArgs),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runRestore(cmd, args, opts)
 		},
 	}
 
-	cmd.Flags().BoolVar(&opts.Verify, "verify", false, "Verify restored files by checking chunk hashes")
+	cmd.Flags().BoolVar(&opts.Verify, "verify", false,
+		"Verify restored files by checking chunk hashes")
 
 	return cmd
 }
@@ -73,8 +82,8 @@ func runRestore(cmd *cobra.Command, args []string, opts *RestoreOptions) error {
 	snapshotID := args[0]
 
 	opts.TargetDir = args[1]
-	if len(args) > 2 {
-		opts.Paths = args[2:]
+	if len(args) > restoreMinArgs {
+		opts.Paths = args[restoreMinArgs:]
 	}
 
 	// Use unified config resolution
@@ -88,7 +97,7 @@ func runRestore(cmd *cobra.Command, args []string, opts *RestoreOptions) error {
 
 	return RunWithApp(cmd.Context(), AppOptions{
 		ConfigPath: configPath,
-		LogOptions: log.LogOptions{
+		LogOptions: log.Options{
 			Verbose: rootFlags.Verbose,
 			Debug:   rootFlags.Debug,
 			Quiet:   rootFlags.Quiet,
@@ -121,7 +130,7 @@ func buildRestoreInvokes(snapshotID string, opts *RestoreOptions) []fx.Option {
 	return []fx.Option{
 		fx.Invoke(func(app *RestoreApp, lc fx.Lifecycle) {
 			lc.Append(fx.Hook{
-				OnStart: func(ctx context.Context) error {
+				OnStart: func(_ context.Context) error {
 					// Start the restore operation in a goroutine
 					go func() {
 						// Run the restore operation
@@ -151,7 +160,7 @@ func buildRestoreInvokes(snapshotID string, opts *RestoreOptions) []fx.Option {
 
 					return nil
 				},
-				OnStop: func(ctx context.Context) error {
+				OnStop: func(_ context.Context) error {
 					log.Debug("Stopping restore operation")
 					app.Vaultik.Cancel()