Field iteration support types

pub enum FieldValue {
  FvBool   { v: boolean },
  FvInt    { v: integer },
  FvLong   { v: integer },
  FvFloat  { v: float },
  FvSingle { v: single },
  FvChar   { v: character },
  FvText   { v: text }
}

Wraps a field value in a type-discriminated enum for compile-time field iteration.

pub struct StructField {
  name:  text not null,
  value: FieldValue,
}

Represents a single struct field during compile-time iteration.

pub fn to_text(self: integer) -> text

Built-in `to_text` impls so primitives satisfy `Printable` automatically. Placed after every OpFormat* / OpAppend* declaration above so format-string interpolation in the bodies can resolve to the relevant built-in. Without these impls, `<T: Printable>(x: T)` rejects built-in element types with "missing to_text" (plan-17 phase 03 — also restores the INTERFACES.md and loft-write-skill claim that built-ins satisfy Printable automatically).

pub fn to_text(self: float) -> text

pub fn to_text(self: single) -> text

pub fn to_text(self: boolean) -> text

pub fn to_text(self: character) -> text

pub fn to_text(self: text) -> text