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

pkg/agehd/agehd_test.go

@@ -190,7 +190,6 @@ func TestDeterministicXPRVDerivation(t *testing.T) {
 
 func TestMnemonicVsXPRVConsistency(t *testing.T) {
 	// FIXME This test is missing!
-
 }
 
 func TestEntropyLength(t *testing.T) {