fix: resolve gochecknoglobals, gosec, lll, and mnd linter errors

- Add nolint comments for BIP85 standard constants (MainNetPrivateKey, TestNetPrivateKey)
- Handle error return from shake.Write() in NewBIP85DRNG
- Fix line length issue by moving nolint comment to separate line
- Add nolint comment for cobra.ExactArgs(2) magic number
- Replace magic number 32 with named constant x25519KeySize in agehd package

internal/secret/secret.go

@@ -286,7 +286,9 @@ func GetCurrentVault(fs afero.Fs, stateDir string) (VaultInterface, error) {
 
 // getCurrentVaultFunc is a function variable that will be set by the vault package
 // to implement the actual GetCurrentVault functionality
-var getCurrentVaultFunc func(fs afero.Fs, stateDir string) (VaultInterface, error) //nolint:gochecknoglobals // Required to break import cycle
+//
+//nolint:gochecknoglobals // Required to break import cycle
+var getCurrentVaultFunc func(fs afero.Fs, stateDir string) (VaultInterface, error)
 
 // RegisterGetCurrentVaultFunc allows the vault package to register its implementation
 // of GetCurrentVault to break the import cycle