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/storage/storer.go

@@ -30,14 +30,15 @@ type ObjectInfo struct {
 	Err  error  // Error for streaming results (nil on success)
 }
 
-// StorageInfo provides human-readable storage configuration.
-type StorageInfo struct {
+// Info provides human-readable storage configuration.
+type Info struct {
 	Type     string // "s3" or "file"
 	Location string // endpoint/bucket for S3, base path for filesystem
 }
 
 // Storer defines the interface for storage backends.
-// All paths are relative to the storage root (bucket/prefix for S3, base directory for filesystem).
+// All paths are relative to the storage root (bucket/prefix for S3, base
+// directory for filesystem).
 type Storer interface {
 	// Put stores data at the specified key.
 	// Parent directories are created automatically for filesystem backends.
@@ -46,7 +47,8 @@ type Storer interface {
 	// PutWithProgress stores data with progress reporting.
 	// Size must be the exact size of the data to store.
 	// The progress callback is called periodically with bytes transferred.
-	PutWithProgress(ctx context.Context, key string, data io.Reader, size int64, progress ProgressCallback) error
+	PutWithProgress(ctx context.Context, key string, data io.Reader,
+		size int64, progress ProgressCallback) error
 
 	// Get retrieves data from the specified key.
 	// The caller must close the returned ReadCloser.
@@ -70,5 +72,5 @@ type Storer interface {
 	ListStream(ctx context.Context, prefix string) <-chan ObjectInfo
 
 	// Info returns human-readable storage location information.
-	Info() StorageInfo
+	Info() Info
 }