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/log/log.go

@@ -1,3 +1,5 @@
+// Package log provides the application-wide structured logger: slog
+// with a colorized TTY handler on terminals and JSON output otherwise.
 package log
 
 import (
@@ -12,12 +14,12 @@ import (
 	"golang.org/x/term"
 )
 
-// LogLevel represents the logging level.
-type LogLevel int
+// Level represents the logging level.
+type Level int
 
 const (
 	// LevelFatal represents a fatal error level that will exit the program.
-	LevelFatal LogLevel = iota
+	LevelFatal Level = iota
 	// LevelError represents an error level.
 	LevelError
 	// LevelWarn represents a warning level.
@@ -38,6 +40,7 @@ type Config struct {
 	Quiet   bool
 }
 
+//nolint:gochecknoglobals // package-level logger is the package's purpose
 var logger *slog.Logger
 
 // Initialize sets up the global logger based on the provided configuration.
@@ -45,18 +48,19 @@ func Initialize(cfg Config) {
 	// Determine log level based on configuration
 	var level slog.Level
 
-	if cfg.Cron || cfg.Quiet {
+	switch {
+	case cfg.Cron || cfg.Quiet:
 		// In cron/quiet mode keep warnings and errors visible — the
 		// whole point of --cron is to stay silent only on total
 		// success, so that anything cron emails to root is genuinely
 		// "something went wrong, look at it." A backup with stuck
 		// permission errors or skipped files should NOT be silent.
 		level = slog.LevelWarn
-	} else if cfg.Debug || strings.Contains(os.Getenv("GODEBUG"), "vaultik") {
+	case cfg.Debug || strings.Contains(os.Getenv("GODEBUG"), "vaultik"):
 		level = slog.LevelDebug
-	} else if cfg.Verbose {
+	case cfg.Verbose:
 		level = slog.LevelInfo
-	} else {
+	default:
 		level = slog.LevelWarn
 	}
 
@@ -78,9 +82,13 @@ func Initialize(cfg Config) {
 	slog.SetDefault(logger)
 }
 
+// callerSkipFrames is the number of stack frames between runtime.Caller
+// and the code that invoked the package-level logging function.
+const callerSkipFrames = 2
+
 // getCaller returns the caller information as a string
-func getCaller(skip int) string {
-	_, file, line, ok := runtime.Caller(skip)
+func getCaller() string {
+	_, file, line, ok := runtime.Caller(callerSkipFrames)
 	if !ok {
 		return "unknown"
 	}
@@ -92,7 +100,7 @@ func getCaller(skip int) string {
 func Fatal(msg string, args ...any) {
 	if logger != nil {
 		// Add caller info to args
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Error(msg, args...)
 	}
 
@@ -107,7 +115,7 @@ func Fatalf(format string, args ...any) {
 // Error logs an error message.
 func Error(msg string, args ...any) {
 	if logger != nil {
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Error(msg, args...)
 	}
 }
@@ -120,7 +128,7 @@ func Errorf(format string, args ...any) {
 // Warn logs a warning message.
 func Warn(msg string, args ...any) {
 	if logger != nil {
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Warn(msg, args...)
 	}
 }
@@ -133,7 +141,7 @@ func Warnf(format string, args ...any) {
 // Notice logs a notice message (mapped to Info level).
 func Notice(msg string, args ...any) {
 	if logger != nil {
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Info(msg, args...)
 	}
 }
@@ -146,7 +154,7 @@ func Noticef(format string, args ...any) {
 // Info logs an informational message.
 func Info(msg string, args ...any) {
 	if logger != nil {
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Info(msg, args...)
 	}
 }
@@ -159,7 +167,7 @@ func Infof(format string, args ...any) {
 // Debug logs a debug message.
 func Debug(msg string, args ...any) {
 	if logger != nil {
-		args = append(args, "caller", getCaller(2))
+		args = append(args, "caller", getCaller())
 		logger.Debug(msg, args...)
 	}
 }
@@ -179,7 +187,7 @@ func With(args ...any) *slog.Logger {
 }
 
 // WithContext returns a logger with the provided context.
-func WithContext(ctx context.Context) *slog.Logger {
+func WithContext(_ context.Context) *slog.Logger {
 	return logger
 }