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/cascade_debug_test.go

@@ -1,3 +1,4 @@
+//nolint:testpackage // inspects the unexported database connection
 package database
 
 import (
@@ -9,25 +10,13 @@ import (
 	"sneak.berlin/go/vaultik/internal/types"
 )
 
-// TestCascadeDeleteDebug tests cascade delete with debug output
-func TestCascadeDeleteDebug(t *testing.T) {
-	db, cleanup := setupTestDB(t)
-	defer cleanup()
+// createCascadeFixtures creates a file with three chunk mappings for the
+// cascade-delete test.
+func createCascadeFixtures(t *testing.T, repos *Repositories) *File {
+	t.Helper()
 
 	ctx := context.Background()
-	repos := NewRepositories(db)
 
-	// Check if foreign keys are enabled
-	var fkEnabled int
-
-	err := db.conn.QueryRow("PRAGMA foreign_keys").Scan(&fkEnabled)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	t.Logf("Foreign keys enabled: %d", fkEnabled)
-
-	// Create a file
 	file := &File{
 		Path:  "/cascade-test.txt",
 		MTime: time.Now().Truncate(time.Second),
@@ -37,7 +26,7 @@ func TestCascadeDeleteDebug(t *testing.T) {
 		GID:   1000,
 	}
 
-	err = repos.Files.Create(ctx, nil, file)
+	err := repos.Files.Create(ctx, nil, file)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -67,9 +56,56 @@ func TestCascadeDeleteDebug(t *testing.T) {
 			t.Fatalf("failed to create file chunk: %v", err)
 		}
 
-		t.Logf("Created file chunk mapping: file_id=%s, idx=%d, chunk=%s", fc.FileID, fc.Idx, fc.ChunkHash)
+		t.Logf("Created file chunk mapping: file_id=%s, idx=%d, chunk=%s",
+			fc.FileID, fc.Idx, fc.ChunkHash)
 	}
 
+	return file
+}
+
+// logCascadeDebugInfo logs foreign-key state and the file_chunks table
+// definition for cascade-delete debugging.
+func logCascadeDebugInfo(ctx context.Context, t *testing.T, db *DB) {
+	t.Helper()
+
+	// Check if foreign keys are enabled
+	var fkEnabled int
+
+	err := db.conn.QueryRowContext(ctx, "PRAGMA foreign_keys").Scan(&fkEnabled)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Logf("Foreign keys enabled: %d", fkEnabled)
+
+	// Check the foreign key constraint
+	var fkInfo string
+
+	err = db.conn.QueryRowContext(ctx, `
+		SELECT sql FROM sqlite_master
+		WHERE type='table' AND name='file_chunks'
+	`).Scan(&fkInfo)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Logf("file_chunks table definition:\n%s", fkInfo)
+}
+
+// TestCascadeDeleteDebug tests cascade delete with debug output
+func TestCascadeDeleteDebug(t *testing.T) {
+	t.Parallel()
+
+	db, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	ctx := context.Background()
+	repos := NewRepositories(db)
+
+	logCascadeDebugInfo(ctx, t, db)
+
+	file := createCascadeFixtures(t, repos)
+
 	// Verify file chunks exist
 	fileChunks, err := repos.FileChunks.GetByFileID(ctx, file.ID)
 	if err != nil {
@@ -78,19 +114,6 @@ func TestCascadeDeleteDebug(t *testing.T) {
 
 	t.Logf("File chunks before delete: %d", len(fileChunks))
 
-	// Check the foreign key constraint
-	var fkInfo string
-
-	err = db.conn.QueryRow(`
-		SELECT sql FROM sqlite_master 
-		WHERE type='table' AND name='file_chunks'
-	`).Scan(&fkInfo)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	t.Logf("file_chunks table definition:\n%s", fkInfo)
-
 	// Delete the file
 	t.Log("Deleting file...")
 
@@ -122,7 +145,9 @@ func TestCascadeDeleteDebug(t *testing.T) {
 	// Manually check the database
 	var count int
 
-	err = db.conn.QueryRow("SELECT COUNT(*) FROM file_chunks WHERE file_id = ?", file.ID).Scan(&count)
+	err = db.conn.QueryRowContext(ctx,
+		"SELECT COUNT(*) FROM file_chunks WHERE file_id = ?", file.ID,
+	).Scan(&count)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -133,7 +158,8 @@ func TestCascadeDeleteDebug(t *testing.T) {
 		t.Errorf("expected 0 file chunks after cascade delete, got %d", len(fileChunks))
 		// List the remaining chunks
 		for _, fc := range fileChunks {
-			t.Logf("Remaining chunk: file_id=%s, idx=%d, chunk=%s", fc.FileID, fc.Idx, fc.ChunkHash)
+			t.Logf("Remaining chunk: file_id=%s, idx=%d, chunk=%s",
+				fc.FileID, fc.Idx, fc.ChunkHash)
 		}
 	}
 }