fix: resolve exported type stuttering issues (revive)

- Rename VaultMetadata to Metadata in internal/vault package to avoid stuttering
- Rename BIP85DRNG to DRNG in pkg/bip85 package to avoid stuttering
- Update all references in code and tests

internal/cli/integration_test.go

@@ -1283,6 +1283,7 @@ func test18AgeKeyOperations(t *testing.T, tempDir, secretPath, testMnemonic stri
 			fmt.Sprintf("HOME=%s", os.Getenv("HOME")),
 		}
 		output, err := cmd.CombinedOutput()
+
 		return string(output), err
 	}
 
@@ -1349,6 +1350,7 @@ func test19DisasterRecovery(t *testing.T, tempDir, secretPath, testMnemonic stri
 			fmt.Sprintf("HOME=%s", os.Getenv("HOME")),
 		}
 		output, err := cmd.CombinedOutput()
+
 		return string(output), err
 	}
 
@@ -1443,6 +1445,7 @@ func test20VersionTimestamps(t *testing.T, tempDir, secretPath, testMnemonic str
 			fmt.Sprintf("HOME=%s", os.Getenv("HOME")),
 		}
 		output, err := cmd.CombinedOutput()
+
 		return string(output), err
 	}
 
@@ -2076,6 +2079,7 @@ func readFile(t *testing.T, path string) []byte {
 	t.Helper()
 	data, err := os.ReadFile(path)
 	require.NoError(t, err, "Should be able to read file: %s", path)
+
 	return data
 }
 
@@ -2125,6 +2129,7 @@ func copyDir(src, dst string) error {
 			}
 		}
 	}
+
 	return nil
 }