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/vaultik/blob_fetch_hash_test.go

@@ -14,20 +14,17 @@ import (
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )
 
-// TestFetchAndDecryptBlobVerifiesHash verifies that FetchAndDecryptBlob checks
-// the double-SHA-256 hash of the decrypted plaintext against the expected blob hash.
-func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
-	identity, err := age.GenerateX25519Identity()
-	if err != nil {
-		t.Fatalf("generating identity: %v", err)
-	}
-
-	// Create test data and encrypt it using blobgen.Writer
-	plaintext := []byte("hello world test data for blob hash verification")
+// buildHashTestBlob encrypts plaintext with blobgen.Writer and returns
+// the encrypted bytes plus the expected double-SHA-256 hash.
+func buildHashTestBlob(
+	t *testing.T, identity *age.X25519Identity, plaintext []byte,
+) ([]byte, string) {
+	t.Helper()
 
 	var encBuf bytes.Buffer
 
-	writer, err := blobgen.NewWriter(&encBuf, 1, []string{identity.Recipient().String()})
+	writer, err := blobgen.NewWriter(&encBuf, 1,
+		[]string{identity.Recipient().String()})
 	if err != nil {
 		t.Fatalf("creating blobgen writer: %v", err)
 	}
@@ -42,9 +39,8 @@ func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
 		t.Fatalf("closing writer: %v", err)
 	}
 
-	encryptedData := encBuf.Bytes()
-
-	// Compute correct double-SHA-256 hash of the plaintext (matches blobgen.Writer.Sum256)
+	// Compute the double-SHA-256 hash of the plaintext (matches
+	// blobgen.Writer.Sum256).
 	firstHash := sha256.Sum256(plaintext)
 	secondHash := sha256.Sum256(firstHash[:])
 	correctHash := hex.EncodeToString(secondHash[:])
@@ -52,12 +48,30 @@ func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
 	// Verify our hash matches what blobgen.Writer produces
 	writerHash := hex.EncodeToString(writer.Sum256())
 	if correctHash != writerHash {
-		t.Fatalf("hash computation mismatch: manual=%s, writer=%s", correctHash, writerHash)
+		t.Fatalf("hash computation mismatch: manual=%s, writer=%s",
+			correctHash, writerHash)
 	}
 
+	return encBuf.Bytes(), correctHash
+}
+
+// TestFetchAndDecryptBlobVerifiesHash verifies that FetchAndDecryptBlob checks
+// the double-SHA-256 hash of the decrypted plaintext against the expected blob hash.
+func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
+	t.Parallel()
+
+	identity, err := age.GenerateX25519Identity()
+	if err != nil {
+		t.Fatalf("generating identity: %v", err)
+	}
+
+	plaintext := []byte("hello world test data for blob hash verification")
+	encryptedData, correctHash := buildHashTestBlob(t, identity, plaintext)
+
 	// Set up mock storage with the blob at the correct path
 	mockStorage := NewMockStorer()
-	blobPath := "blobs/" + correctHash[:2] + "/" + correctHash[2:4] + "/" + correctHash
+	blobPath := "blobs/" + correctHash[:2] + "/" +
+		correctHash[2:4] + "/" + correctHash
 
 	mockStorage.mu.Lock()
 	mockStorage.data[blobPath] = encryptedData
@@ -67,7 +81,10 @@ func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
 	ctx := context.Background()
 
 	t.Run("correct hash succeeds", func(t *testing.T) {
-		rc, err := tv.FetchAndDecryptBlob(ctx, correctHash, int64(len(encryptedData)), identity)
+		t.Parallel()
+
+		rc, err := tv.FetchAndDecryptBlob(
+			ctx, correctHash, int64(len(encryptedData)), identity)
 		if err != nil {
 			t.Fatalf("expected success, got error: %v", err)
 		}
@@ -88,6 +105,8 @@ func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
 	})
 
 	t.Run("wrong hash fails", func(t *testing.T) {
+		t.Parallel()
+
 		// Use a fake hash that doesn't match the actual plaintext
 		fakeHash := strings.Repeat("ab", 32) // 64 hex chars
 		fakePath := "blobs/" + fakeHash[:2] + "/" + fakeHash[2:4] + "/" + fakeHash
@@ -96,7 +115,8 @@ func TestFetchAndDecryptBlobVerifiesHash(t *testing.T) {
 		mockStorage.data[fakePath] = encryptedData
 		mockStorage.mu.Unlock()
 
-		rc, err := tv.FetchAndDecryptBlob(ctx, fakeHash, int64(len(encryptedData)), identity)
+		rc, err := tv.FetchAndDecryptBlob(
+			ctx, fakeHash, int64(len(encryptedData)), identity)
 		if err != nil {
 			t.Fatalf("unexpected error opening stream: %v", err)
 		}