fix: refine presentation slides 2, 5 and 7

scripts/browser/presentation.cjs

@@ -1,4 +1,5 @@
 const {chromium}=require('playwright');
+const staircaseFits=require('./presentation-staircase.cjs');
 const fs=require('node:fs'); const assert=require('node:assert/strict');
 (async()=>{
  const base=process.argv[2]||'http://127.0.0.1:4179'; const root='/eldorado-v1/documentation/';const url=base+root+'presentations/less-prompting-more-shipping/';
@@ -20,7 +21,8 @@ const fs=require('node:fs'); const assert=require('node:assert/strict');
      const slide=Reveal.getCurrentSlide(),r=slide.getBoundingClientRect();
      return [...slide.querySelectorAll('svg,text,.journey,.learning-loop,.contribution-grid,h1,h2,p,li,td,th,.rail,.gate,.facts,.flow,.roles,.timeline,.capacity,.measure-list,.contrast,.comparison,.choices,.ledger')].filter(e=>!e.closest('.notes')&&e.getBoundingClientRect().width>0).filter(e=>{const b=e.getBoundingClientRect();return b.bottom>r.bottom+1||b.right>r.right+1||b.left<r.left-1||b.top<r.top-1}).map(e=>e.textContent.slice(0,60));
     });
-    if(i===4)assert(await page.evaluate(()=>[...document.querySelectorAll('#contributors .contribution-grid>div')].every(e=>{const a=e.querySelector('span').getBoundingClientRect(), arrow=e.querySelector('i').getBoundingClientRect(), b=e.querySelector('b').getBoundingClientRect();return a.bottom<=arrow.top+2&&arrow.bottom<=b.top+2&&Math.abs((a.left+a.right-b.left-b.right)/2)<2&&getComputedStyle(e.querySelector('i')).transform==='matrix(0, 1, -1, 0, 0, 0)'})),'contribution arrows must point down to their own phase');
+    if(i===6)assert(await page.evaluate(staircaseFits),'staircase aligns each arrow with its intended steps');
+   if(i===4)assert(await page.evaluate(()=>[...document.querySelectorAll('#contributors .contribution-grid>div')].every(e=>{const a=e.querySelector('span').getBoundingClientRect(), arrow=e.querySelector('i').getBoundingClientRect(), b=e.querySelector('b').getBoundingClientRect();return a.bottom<=arrow.top+2&&arrow.bottom<=b.top+2&&Math.abs((a.left+a.right-b.left-b.right)/2)<2&&getComputedStyle(e.querySelector('i')).transform==='matrix(0, 1, -1, 0, 0, 0)'})),'contribution arrows must point down to their own phase');
    bounds.push({slide:i+1,overflow:bad});
     await page.screenshot({path:`${out}/${viewport.width}-slide-${String(i+1).padStart(2,'0')}.png`});
    }