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/types/types.go

@@ -1,16 +1,26 @@
-// Package types provides custom types for better type safety across the vaultik codebase.
-// Using distinct types for IDs, hashes, paths, and credentials prevents accidental
-// mixing of semantically different values that happen to share the same underlying type.
+// Package types provides custom types for better type safety across the
+// vaultik codebase. Using distinct types for IDs, hashes, paths, and
+// credentials prevents accidental mixing of semantically different values
+// that happen to share the same underlying type.
 package types
 
 import (
 	"database/sql/driver"
+	"errors"
 	"fmt"
 
 	"github.com/google/uuid"
 )
 
+// errCannotScan is returned when a database value cannot be scanned into
+// an ID type.
+var errCannotScan = errors.New("cannot scan value")
+
 // FileID is a UUID identifying a file record in the database.
+//
+// used on values.
+//
+//nolint:recvcheck // Scan requires a pointer receiver; String/Value are
 type FileID uuid.UUID
 
 // NewFileID generates a new random FileID.
@@ -54,7 +64,7 @@ func (id *FileID) Scan(src any) error {
 	case []byte:
 		s = string(v)
 	default:
-		return fmt.Errorf("cannot scan %T into FileID", src)
+		return fmt.Errorf("%w: %T into FileID", errCannotScan, src)
 	}
 
 	parsed, err := uuid.Parse(s)
@@ -69,6 +79,10 @@ func (id *FileID) Scan(src any) error {
 
 // BlobID is a UUID identifying a blob record in the database.
 // This is distinct from BlobHash which is the content-addressed hash of the blob.
+//
+// used on values.
+//
+//nolint:recvcheck // Scan requires a pointer receiver; String/Value are
 type BlobID uuid.UUID
 
 // NewBlobID generates a new random BlobID.
@@ -112,7 +126,7 @@ func (id *BlobID) Scan(src any) error {
 	case []byte:
 		s = string(v)
 	default:
-		return fmt.Errorf("cannot scan %T into BlobID", src)
+		return fmt.Errorf("%w: %T into BlobID", errCannotScan, src)
 	}
 
 	parsed, err := uuid.Parse(s)
@@ -208,6 +222,8 @@ func (p GlobPattern) String() string    { return string(p) }
 func (k AgeSecretKey) String() string       { return "[REDACTED]" }
 func (k AWSSecretAccessKey) String() string { return "[REDACTED]" }
 
-// Raw returns the actual value for sensitive types when explicitly needed
-func (k AgeSecretKey) Raw() string       { return string(k) }
+// Raw returns the actual value for sensitive types when explicitly needed.
+func (k AgeSecretKey) Raw() string { return string(k) }
+
+// Raw returns the actual value for sensitive types when explicitly needed.
 func (k AWSSecretAccessKey) Raw() string { return string(k) }