Update golangci-lint to v2.12.2 with canonical config (#62)

Updates golangci-lint to v2.12.2 everywhere it is pinned and installs the canonical `.golangci.yml`, then remediates every finding the new linter/config surfaces so `make check` is green.

## Version bump

- `Dockerfile` lint stage: `golangci/golangci-lint:v2.11.3-alpine` -> `v2.12.2-alpine` (digest-pinned, date comment updated)
- `Makefile` `deps` target: `go install` moved from the old v1 module path at `@latest` to the pinned `github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2`
- `.golangci.yml` replaced with the canonical config (v2 schema; settings under `linters.settings` so the thresholds actually apply; `default: all` with the standard six disables)
- `script/bootstrap` installs golangci-lint via the system package manager and carries no version pin, so it is unchanged
- CI (`.gitea/workflows/check.yml`) only runs `script/cibuild`, so it needed no change

## Lint remediation

The canonical config surfaced ~3,300 findings across 56k lines. All are fixed, behavior-preserving; incorporates and supersedes the per-package mechanical passes already merged to `main` (refs #61). Highlights:

- `err113`: dynamic errors replaced with package sentinels + `%w` wrapping; comparisons via `errors.Is`
- `goprintffuncname`: printf-style helpers renamed with an `f` suffix (`ui.Writer` message methods, `cli.ReportErrorf`, `database.Fatalf`) and all call sites updated
- `revive` stutter renames: `blob.Handler`, `blob.WithReader`, `blob.ChunkPosition`, `storage.URL`, `storage.Info`; missing doc comments added
- `contextcheck`/`noctx`: `context.Context` threaded through `blob.Packer` and the scanner call sites; context-aware `exec`/`sql` variants
- `funlen`/`cyclop`/`gocognit`/`dupl`: oversized and duplicated functions split into focused helpers (production and test code)
- tests: `t.Parallel()` added where safe (global logger init kept in the serial phase for `-race`), `t.TempDir()`/`t.Helper()` adopted, several suites converted to external test packages
- `gosec`: bounded integer conversions, `ReadHeaderTimeout` on the test HTTP server; remaining warnings suppressed per-site with justifications
- remaining `nolint` directives are rare, targeted, and each carries a reason (e.g. `nilnil` not-found contract in the repository layer, fx module globals, on-disk snake_case struct tags)
- removed the deprecated `log.LogOptions` alias (callers migrated to `log.Options`)

`make check` (tests with `-race`, lint, fmt-check) passes.

Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #62
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/database/repository_debug_test.go

@@ -1,3 +1,4 @@
+//nolint:testpackage // inspects the unexported database connection
 package database
 
 import (
@@ -6,15 +7,50 @@ import (
 	"time"
 )
 
-// TestOrphanedFileCleanupDebug tests orphaned file cleanup with debug output
-func TestOrphanedFileCleanupDebug(t *testing.T) {
-	db, cleanup := setupTestDB(t)
-	defer cleanup()
+// logSnapshotFileIDs logs every file_id present in snapshot_files.
+func logSnapshotFileIDs(t *testing.T, db *DB) {
+	t.Helper()
 
 	ctx := context.Background()
-	repos := NewRepositories(db)
 
-	// Create files
+	rows, err := db.conn.QueryContext(ctx, "SELECT file_id FROM snapshot_files")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		err := rows.Close()
+		if err != nil {
+			t.Logf("failed to close rows: %v", err)
+		}
+	}()
+
+	t.Log("Files in snapshot_files:")
+
+	for rows.Next() {
+		var fileID string
+
+		err := rows.Scan(&fileID)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		t.Logf("  - %s", fileID)
+	}
+
+	err = rows.Err()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// TestOrphanedFileCleanupDebug tests orphaned file cleanup with debug output
+// createOrphanDebugFixtures creates one orphaned file, one referenced
+// file, and the snapshot that will reference the latter.
+func createOrphanDebugFixtures(
+	ctx context.Context, t *testing.T, repos *Repositories,
+) (*File, *File, *Snapshot) {
+	t.Helper()
+
 	file1 := &File{
 		Path:  "/orphaned.txt",
 		MTime: time.Now().Truncate(time.Second),
@@ -48,8 +84,8 @@ func TestOrphanedFileCleanupDebug(t *testing.T) {
 
 	// Create a snapshot and reference only file2
 	snapshot := &Snapshot{
-		ID:        "test-snapshot",
-		Hostname:  "test-host",
+		ID:        internalTestSnapshotID,
+		Hostname:  internalTestHost,
 		StartedAt: time.Now(),
 	}
 
@@ -60,18 +96,26 @@ func TestOrphanedFileCleanupDebug(t *testing.T) {
 
 	t.Logf("Created snapshot: %s", snapshot.ID)
 
+	return file1, file2, snapshot
+}
+
+func TestOrphanedFileCleanupDebug(t *testing.T) {
+	t.Parallel()
+
+	db, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	ctx := context.Background()
+	repos := NewRepositories(db)
+
+	file1, file2, snapshot := createOrphanDebugFixtures(ctx, t, repos)
+
 	// Check snapshot_files before adding
-	var count int
-
-	err = db.conn.QueryRow("SELECT COUNT(*) FROM snapshot_files").Scan(&count)
-	if err != nil {
-		t.Fatal(err)
-	}
-
+	count := countRow(t, db, "SELECT COUNT(*) FROM snapshot_files")
 	t.Logf("snapshot_files count before add: %d", count)
 
 	// Add file2 to snapshot
-	err = repos.Snapshots.AddFileByID(ctx, nil, snapshot.ID.String(), file2.ID)
+	err := repos.Snapshots.AddFileByID(ctx, nil, snapshot.ID.String(), file2.ID)
 	if err != nil {
 		t.Fatalf("failed to add file to snapshot: %v", err)
 	}
@@ -79,44 +123,14 @@ func TestOrphanedFileCleanupDebug(t *testing.T) {
 	t.Logf("Added file2 to snapshot")
 
 	// Check snapshot_files after adding
-	err = db.conn.QueryRow("SELECT COUNT(*) FROM snapshot_files").Scan(&count)
-	if err != nil {
-		t.Fatal(err)
-	}
-
+	count = countRow(t, db, "SELECT COUNT(*) FROM snapshot_files")
 	t.Logf("snapshot_files count after add: %d", count)
 
 	// Check which files are referenced
-	rows, err := db.conn.Query("SELECT file_id FROM snapshot_files")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer func() {
-		err := rows.Close()
-		if err != nil {
-			t.Logf("failed to close rows: %v", err)
-		}
-	}()
-
-	t.Log("Files in snapshot_files:")
-
-	for rows.Next() {
-		var fileID string
-
-		err := rows.Scan(&fileID)
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		t.Logf("  - %s", fileID)
-	}
+	logSnapshotFileIDs(t, db)
 
 	// Check files before cleanup
-	err = db.conn.QueryRow("SELECT COUNT(*) FROM files").Scan(&count)
-	if err != nil {
-		t.Fatal(err)
-	}
-
+	count = countRow(t, db, countFilesQuery)
 	t.Logf("Files count before cleanup: %d", count)
 
 	// Run orphaned cleanup
@@ -128,11 +142,7 @@ func TestOrphanedFileCleanupDebug(t *testing.T) {
 	t.Log("Ran orphaned cleanup")
 
 	// Check files after cleanup
-	err = db.conn.QueryRow("SELECT COUNT(*) FROM files").Scan(&count)
-	if err != nil {
-		t.Fatal(err)
-	}
-
+	count = countRow(t, db, countFilesQuery)
 	t.Logf("Files count after cleanup: %d", count)
 
 	// List remaining files
@@ -156,18 +166,12 @@ func TestOrphanedFileCleanupDebug(t *testing.T) {
 	if orphanedFile != nil {
 		t.Error("orphaned file should have been deleted")
 		// Let's check why it wasn't deleted
-		var exists bool
-
-		err = db.conn.QueryRow(`
+		stillReferenced := countRow(t, db, `
 			SELECT EXISTS(
-				SELECT 1 FROM snapshot_files 
+				SELECT 1 FROM snapshot_files
 				WHERE file_id = ?
-			)`, file1.ID).Scan(&exists)
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		t.Logf("File1 exists in snapshot_files: %v", exists)
+			)`, file1.ID)
+		t.Logf("File1 exists in snapshot_files: %v", stillReferenced != 0)
 	} else {
 		t.Log("Orphaned file was correctly deleted")
 	}