Models with encrypted columns can use Options now

[nz]

Fixes #41.

Before, a model with an encrypted column could not save at all once it used this gem: every save raised an error. That is because Rails adds its own hidden length check to encrypted columns, and that check cannot read a value inside an Option. Now encrypted columns are simply left alone, so saves work. You can also name other columns to leave alone with errgonomic_optional_except.

Detail

• ActiveRecord Encryption registers a length validator outside Model.validators (encryptable_record.rb:126-142: load_schema! → validate_column_size → validates_length_of), whose validate_each calls to_s on the value — and Option#to_s raises by design.
• Commit 1: the concern excludes Array(encrypted_attributes) when computing the wrapped set. That alone misses the reported case, where encrypts is declared after the include (the Set is still nil at include time), so the concern also overrides encrypts to call super then un-wrap the named reader (remove_method lets dispatch fall back to AR's attribute methods). Both declaration orders are tested.
• Commit 2: errgonomic_optional_except :attr, ..., callable before the include, as an escape hatch for whatever conflict shows up next.
• Commit 3: the encrypted-attribute exclusion is named compromise 5 in the concern header and README, per the compromise-list rule that new integration exceptions get a design discussion and a list entry. errgonomic_optional_except is deliberately kept off the list: it is configuration, not a semantic exception.

Review note: the encrypts override forwards Rails 8.1's (*names, **options) signature and relies on super reaching EncryptableRecord::ClassMethods; it is the most brittle piece of this batch and worth a close look.

Tests: encrypted-column model saves, encrypted reader returns the raw value, sibling nullable column still wrapped, absent encrypted value round-trips, errgonomic_optional_except skips named attributes.

[lutzcc1]

Although practical, this Options exception seems a bit obscure.