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/blob_chunks.go

@@ -7,15 +7,21 @@ import (
 	"fmt"
 )
 
+// BlobChunkRepository provides access to the blob_chunks table, which maps
+// blobs to the chunks they contain (with offset and length).
 type BlobChunkRepository struct {
 	db *DB
 }
 
+// NewBlobChunkRepository creates a BlobChunkRepository backed by db.
 func NewBlobChunkRepository(db *DB) *BlobChunkRepository {
 	return &BlobChunkRepository{db: db}
 }
 
-func (r *BlobChunkRepository) Create(ctx context.Context, tx *sql.Tx, bc *BlobChunk) error {
+// Create inserts a blob_chunks row, using tx when non-nil.
+func (r *BlobChunkRepository) Create(
+	ctx context.Context, tx *sql.Tx, bc *BlobChunk,
+) error {
 	query := `
 		INSERT INTO blob_chunks (blob_id, chunk_hash, offset, length)
 		VALUES (?, ?, ?, ?)
@@ -35,7 +41,11 @@ func (r *BlobChunkRepository) Create(ctx context.Context, tx *sql.Tx, bc *BlobCh
 	return nil
 }
 
-func (r *BlobChunkRepository) GetByBlobID(ctx context.Context, blobID string) ([]*BlobChunk, error) {
+// GetByBlobID returns all chunks contained in the given blob, ordered by
+// their offset within the blob.
+func (r *BlobChunkRepository) GetByBlobID(
+	ctx context.Context, blobID string,
+) ([]*BlobChunk, error) {
 	query := `
 		SELECT blob_id, chunk_hash, offset, length
 		FROM blob_chunks
@@ -65,7 +75,11 @@ func (r *BlobChunkRepository) GetByBlobID(ctx context.Context, blobID string) ([
 	return blobChunks, rows.Err()
 }
 
-func (r *BlobChunkRepository) GetByChunkHash(ctx context.Context, chunkHash string) (*BlobChunk, error) {
+// GetByChunkHash returns one blob_chunks row containing the given chunk,
+// or nil if the chunk is not packed in any blob.
+func (r *BlobChunkRepository) GetByChunkHash(
+	ctx context.Context, chunkHash string,
+) (*BlobChunk, error) {
 	query := `
 		SELECT blob_id, chunk_hash, offset, length
 		FROM blob_chunks
@@ -87,7 +101,7 @@ func (r *BlobChunkRepository) GetByChunkHash(ctx context.Context, chunkHash stri
 	if errors.Is(err, sql.ErrNoRows) {
 		LogSQL("GetByChunkHash", "No rows found", chunkHash)
 
-		return nil, nil
+		return nil, nil //nolint:nilnil // nil,nil signals not-found; callers check nil
 	}
 
 	if err != nil {
@@ -102,7 +116,9 @@ func (r *BlobChunkRepository) GetByChunkHash(ctx context.Context, chunkHash stri
 }
 
 // GetByChunkHashTx retrieves a blob chunk within a transaction
-func (r *BlobChunkRepository) GetByChunkHashTx(ctx context.Context, tx *sql.Tx, chunkHash string) (*BlobChunk, error) {
+func (r *BlobChunkRepository) GetByChunkHashTx(
+	ctx context.Context, tx *sql.Tx, chunkHash string,
+) (*BlobChunk, error) {
 	query := `
 		SELECT blob_id, chunk_hash, offset, length
 		FROM blob_chunks
@@ -124,7 +140,7 @@ func (r *BlobChunkRepository) GetByChunkHashTx(ctx context.Context, tx *sql.Tx,
 	if errors.Is(err, sql.ErrNoRows) {
 		LogSQL("GetByChunkHashTx", "No rows found", chunkHash)
 
-		return nil, nil
+		return nil, nil //nolint:nilnil // nil,nil signals not-found; callers check nil
 	}
 
 	if err != nil {
@@ -138,13 +154,14 @@ func (r *BlobChunkRepository) GetByChunkHashTx(ctx context.Context, tx *sql.Tx,
 	return &bc, nil
 }
 
-// DeleteOrphaned deletes blob_chunks entries where either the blob or chunk no longer exists
+// DeleteOrphaned deletes blob_chunks entries where either the blob or the
+// chunk no longer exists.
 func (r *BlobChunkRepository) DeleteOrphaned(ctx context.Context) error {
 	// Delete blob_chunks where the blob doesn't exist
 	query1 := `
-		DELETE FROM blob_chunks 
+		DELETE FROM blob_chunks
 		WHERE NOT EXISTS (
-			SELECT 1 FROM blobs 
+			SELECT 1 FROM blobs
 			WHERE blobs.id = blob_chunks.blob_id
 		)
 	`
@@ -156,9 +173,9 @@ func (r *BlobChunkRepository) DeleteOrphaned(ctx context.Context) error {
 
 	// Delete blob_chunks where the chunk doesn't exist
 	query2 := `
-		DELETE FROM blob_chunks 
+		DELETE FROM blob_chunks
 		WHERE NOT EXISTS (
-			SELECT 1 FROM chunks 
+			SELECT 1 FROM chunks
 			WHERE chunks.chunk_hash = blob_chunks.chunk_hash
 		)
 	`