v1.3.0

v1.3.0 (2026-10-08)

• Forward line references resolve: &67 on line 65 answers with
  line 67's result. The spec always promised references to "any
  line, above or below", but the engine evaluated one strict
  top-down pass, so anything pointing downward stayed blank
  forever. The sheet now re-evaluates - whole-sheet passes seeded
  with the previous pass's results, stopping when the rendered
  answers stop changing (a cap of 8 bounds it) - so chains resolve
  one link per pass and a summary line at the top of a section can
  cite the derivation at the bottom. Cycles never ignite: no line
  in a circular chain is ever seeded, so a cycle stays blank
  rather than showing a wrong number, and sheets without forward
  references still cost exactly one pass. Unit lines resolve
  forward too (&2 kg * 2 over 3 kg answers 6 kg). The starter
  sheet's Line references section demos it live: a backward ref and
  a forward ref, both answering.
• A research wave (three agents: engine design, reference-app
  semantics, app blast radius) drove the design. The interesting
  negative result: iteration-as-cycles (a Newton's-method guess
  referencing itself) does NOT work under re-pass evaluation -
  cycles never ignite and seeds reset each pass - so converging
  iterations stay with recursive functions, where they are already
  sound.