sieve-render

name	sieve-render
description	Private sieve subskill. Invoked by the sieve controller after each pass; not user-invocable. Reads sieve.state and draws the current grid — remaining primes vs. struck (composite) numbers.
user-invocable	false

Sieve render — draw the current grid

You are a private subskill (user-invocable: false), invoked by the sieve controller to visualize the current state. You take no meaningful argument.

Do exactly this:

1. Read sieve.state:

   • n from the n=<n> header line.
   • The struck set = the union of every number on the right-hand side of all strike p=... -> ... lines.
   • The last pivot = the p from the most recent strike line, if any.

2. Draw a grid of 1..n in a fenced code block, 10 numbers per row, each cell right-aligned to width 4:

   • 1 → render as · (1 is not prime).
   • A struck number → render as · (composite).
   • Any other number (still unmarked, so prime-so-far) → render the number, e.g. 7.

   Example shape for n=30 after striking 2, 3, and 5:

      ·   2   3   ·   5   ·   7   ·   ·   ·
     11   ·  13   ·   ·   ·  17   ·  19   ·
     ·   ·  23   ·   ·   ·   ·   ·  29   ·
   

3. Below the grid, print a one-line legend and status: legend: number = prime so far, · = struck/not prime — and, if there was a last pivot, add (just struck multiples of <last pivot>).

Do not modify sieve.state, strike anything, or invoke other skills. Render only, then return control to the controller.