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/database/local_meta_test.go

@@ -9,6 +9,8 @@ import (
 )
 
 func TestLocalMetaEmptyOnFresh(t *testing.T) {
+	t.Parallel()
+
 	db, err := database.NewTestDB()
 	require.NoError(t, err)
 
@@ -22,6 +24,8 @@ func TestLocalMetaEmptyOnFresh(t *testing.T) {
 }
 
 func TestLocalMetaSetGetRoundTrip(t *testing.T) {
+	t.Parallel()
+
 	db, err := database.NewTestDB()
 	require.NoError(t, err)
 
@@ -30,7 +34,8 @@ func TestLocalMetaSetGetRoundTrip(t *testing.T) {
 	repos := database.NewRepositories(db)
 	ctx := context.Background()
 
-	require.NoError(t, repos.LocalMeta.Set(ctx, database.LocalMetaKeyStorageURL, "file:///mnt/backups"))
+	require.NoError(t, repos.LocalMeta.Set(
+		ctx, database.LocalMetaKeyStorageURL, "file:///mnt/backups"))
 
 	got, err := repos.LocalMeta.Get(ctx, database.LocalMetaKeyStorageURL)
 	require.NoError(t, err)
@@ -38,6 +43,8 @@ func TestLocalMetaSetGetRoundTrip(t *testing.T) {
 }
 
 func TestLocalMetaSetOverwrites(t *testing.T) {
+	t.Parallel()
+
 	db, err := database.NewTestDB()
 	require.NoError(t, err)
 
@@ -46,8 +53,10 @@ func TestLocalMetaSetOverwrites(t *testing.T) {
 	repos := database.NewRepositories(db)
 	ctx := context.Background()
 
-	require.NoError(t, repos.LocalMeta.Set(ctx, database.LocalMetaKeyStorageURL, "s3://old"))
-	require.NoError(t, repos.LocalMeta.Set(ctx, database.LocalMetaKeyStorageURL, "s3://new"))
+	require.NoError(t, repos.LocalMeta.Set(
+		ctx, database.LocalMetaKeyStorageURL, "s3://old"))
+	require.NoError(t, repos.LocalMeta.Set(
+		ctx, database.LocalMetaKeyStorageURL, "s3://new"))
 
 	got, err := repos.LocalMeta.Get(ctx, database.LocalMetaKeyStorageURL)
 	require.NoError(t, err)