Update golangci-lint to v2.12.2 with canonical config (#29)

Bumps golangci-lint from v2.1.6 (digest-only pin in the `Dockerfile` lint stage) to v2.12.2, pinned by tag and digest (Debian-based image).

Replaces `.golangci.yml` with the canonical strict config: all linters enabled except the standard disable list (`exhaustruct`, `depguard`, `godot`, `wsl`, `wrapcheck`, `varnamelen`), `lll` at 88, `funlen` 80/50, `cyclop` 15, `dupl` 100, and test files are now linted (the old config had `tests: false`, an enable-only list of ~20 linters, `lll` 120, and a blanket exclusion of `internal/macse`).

The stricter config surfaced ~1550 findings, all fixed:

- `wsl_v5` (439) / `nlreturn` (24): blank-line insertions
- `lll` (309): line wrapping at 88 columns; long literals split with `+` concatenation, values unchanged
- `noinlineerr` (130): `if err := ...` split into assignment plus check
- `paralleltest` (116): `t.Parallel()` added to tests without shared state; reasoned `//nolint` where `t.Setenv` or shared fixtures forbid it
- `err113` (97): package-level sentinel errors (new `internal/vault/errors.go`), `%w` wrapping, `errors.Is`
- `perfsprint` (74) / `modernize` (39) / `intrange`: `strconv`, `errors.New`, `slices.Contains`, `any`, `SplitSeq`
- `goconst` (40) / `dupword` (41) / `testifylint` (42) / `thelper` (33): constants, assertion fixes, `t.Helper()`
- `noctx` (22): `exec.CommandContext` for gpg/CLI invocations
- `testpackage` (18): black-box tests moved to `_test` packages where they use only exported identifiers; white-box files carry a reasoned `//nolint`
- `funlen`/`cyclop`/`gocognit`/`nestif`/`dupl`: behavior-preserving helper extraction
- assorted singletons: `gosec`, `gosmopolitan`, `funcorder`, `nonamedreturns`, `makezero`, `prealloc`, `godox`, `nolintlint`, `ireturn`, `nilnil`, `gochecknoinits`

## User-visible strings

**None changed.** Every error message this branch composes is byte-identical to the one `main` composes.

The `err113` sentinels are shaped so `fmt.Errorf` reassembles the original text around them: the sentinel carries the fixed words and the caller supplies the interpolated value in the position it has always occupied. Where the value sits mid-sentence the sentinel holds only a fragment (e.g. `vault.ErrVaultNotFound` is `"does not exist"`, composed by its caller as `vault <name> does not exist`); each such sentinel documents the message it participates in.

Verified mechanically, not by inspection: every `fmt.Errorf` and `errors.New` call site in both trees is parsed, the `Error()` text of any sentinel passed to `%w` is substituted in, and the resulting sets of composed message templates are compared. All 350 templates `main` produces are still produced, character for character. The set of lost or altered messages is empty.

## `unlocker list`

`findUnlockerIDByMetadata` returns `(string, error)` rather than signalling failure with an empty ID, so an unreadable `unlockers.d` is no longer indistinguishable from "no matching entry". `UnlockersList` skips such an entry with a warning naming the directory — its behavior before the scan was extracted into a helper — instead of emitting a row under a synthesized fallback ID that no `unlocker remove` or `unlocker select` can match and that suppresses the current-unlocker marker. The duplicate-check and shell-completion callers skip on the same condition, matching their pre-extraction behavior. Covered by `internal/cli/unlockers_list_test.go`.

`TODO.md` records the change plus follow-ups (version-completion TODOs formerly in code comments, darwin-gated files exceeding 88 columns that Linux CI does not lint).

`make check` is green and the pinned v2.12.2 image reports `0 issues.` Note the test suite needs the memlock ulimit from `script/cibuild` for the 10MB memguard test; that requirement is pre-existing.

Not changed: `script/bootstrap` installs golangci-lint via the system package manager (no version pin to bump), and `script/lint` invokes whatever `golangci-lint` is on PATH. golangci-lint v2.12 deprecates `gomodguard` in favor of `gomodguard_v2` (warning only); the canonical config owns that decision.

Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #29
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/vault/path_traversal_test.go

@@ -1,27 +1,27 @@
-package vault
+package vault_test
 
 import (
 	"testing"
 
 	"git.eeqj.de/sneak/secret/internal/secret"
+	"git.eeqj.de/sneak/secret/internal/vault"
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 // TestGetSecretVersionRejectsPathTraversal verifies that GetSecretVersion
 // validates the secret name and rejects path traversal attempts.
 // This is a regression test for https://git.eeqj.de/sneak/secret/issues/13
+//
+//nolint:paralleltest // t.Setenv in parent forbids parallel subtests
 func TestGetSecretVersionRejectsPathTraversal(t *testing.T) {
-	testMnemonic := "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, "test-passphrase")
+	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
 
 	fs := afero.NewMemMapFs()
-	stateDir := "/test/state"
 
-	vlt, err := CreateVault(fs, stateDir, "test-vault")
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
 	require.NoError(t, err)
 
 	// Add a legitimate secret so the vault is set up
@@ -42,42 +42,41 @@ func TestGetSecretVersionRejectsPathTraversal(t *testing.T) {
 	for _, name := range maliciousNames {
 		t.Run(name, func(t *testing.T) {
 			_, err := vlt.GetSecretVersion(name, "")
-			assert.Error(t, err, "GetSecretVersion should reject malicious name: %s", name)
-			assert.Contains(t, err.Error(), "invalid secret name",
+			require.Error(t, err,
+				"GetSecretVersion should reject malicious name: %s", name)
+			require.Contains(t, err.Error(), "invalid secret name",
 				"error should indicate invalid name for: %s", name)
 		})
 	}
 }
 
-// TestGetSecretRejectsPathTraversal verifies GetSecret (which calls GetSecretVersion)
-// also rejects path traversal names.
+// TestGetSecretRejectsPathTraversal verifies GetSecret (which calls
+// GetSecretVersion) also rejects path traversal names.
 func TestGetSecretRejectsPathTraversal(t *testing.T) {
-	testMnemonic := "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, "test-passphrase")
+	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
 
 	fs := afero.NewMemMapFs()
-	stateDir := "/test/state"
 
-	vlt, err := CreateVault(fs, stateDir, "test-vault")
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
 	require.NoError(t, err)
 
 	_, err = vlt.GetSecret("../../../etc/passwd")
-	assert.Error(t, err)
-	assert.Contains(t, err.Error(), "invalid secret name")
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "invalid secret name")
 }
 
 // TestGetSecretObjectRejectsPathTraversal verifies GetSecretObject
 // also validates names and rejects path traversal attempts.
+//
+//nolint:paralleltest // t.Setenv in parent forbids parallel subtests
 func TestGetSecretObjectRejectsPathTraversal(t *testing.T) {
-	testMnemonic := "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
 	t.Setenv(secret.EnvMnemonic, testMnemonic)
-	t.Setenv(secret.EnvUnlockPassphrase, "test-passphrase")
+	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
 
 	fs := afero.NewMemMapFs()
-	stateDir := "/test/state"
 
-	vlt, err := CreateVault(fs, stateDir, "test-vault")
+	vlt, err := vault.CreateVault(fs, testStateDir, testVaultName)
 	require.NoError(t, err)
 
 	maliciousNames := []string{
@@ -89,8 +88,8 @@ func TestGetSecretObjectRejectsPathTraversal(t *testing.T) {
 	for _, name := range maliciousNames {
 		t.Run(name, func(t *testing.T) {
 			_, err := vlt.GetSecretObject(name)
-			assert.Error(t, err, "GetSecretObject should reject: %s", name)
-			assert.Contains(t, err.Error(), "invalid secret name")
+			require.Error(t, err, "GetSecretObject should reject: %s", name)
+			require.Contains(t, err.Error(), "invalid secret name")
 		})
 	}
 }