Fix intrange and G101 linting issues

- Convert for loops to use Go 1.22+ integer ranges in generate.go and helpers.go
- Disable G101 false positives for test vectors and environment variable names
- Add file-level gosec disable for bip85_test.go containing BIP85 test vectors
- Add targeted nolint comments for legitimate test data and constants

internal/secret/pgpunlock_test.go

@@ -35,7 +35,7 @@ func setupNonInteractiveGPG(t *testing.T, tempDir, passphrase, gnupgHomeDir stri
 no-tty
 pinentry-mode loopback
 `
-	if err := os.WriteFile(gpgConfPath, []byte(gpgConfContent), 0600); err != nil {
+	if err := os.WriteFile(gpgConfPath, []byte(gpgConfContent), 0o600); err != nil {
 		t.Fatalf("Failed to write GPG config file: %v", err)
 	}
 
@@ -139,7 +139,7 @@ func TestPGPUnlockerWithRealFS(t *testing.T) {
 
 	// Create a temporary GNUPGHOME
 	gnupgHomeDir := filepath.Join(tempDir, "gnupg")
-	if err := os.MkdirAll(gnupgHomeDir, 0700); err != nil {
+	if err := os.MkdirAll(gnupgHomeDir, 0o700); err != nil {
 		t.Fatalf("Failed to create GNUPGHOME: %v", err)
 	}
 
@@ -176,7 +176,7 @@ Passphrase: ` + testPassphrase + `
 %commit
 %echo Key generation completed
 `
-	if err := os.WriteFile(batchFile, []byte(batchContent), 0600); err != nil {
+	if err := os.WriteFile(batchFile, []byte(batchContent), 0o600); err != nil {
 		t.Fatalf("Failed to write batch file: %v", err)
 	}