refactor: retire the hand-written site

Deletes the pre-Astro pages, scripts, and stylesheets that the migration
replaced, and moves the ones it did not replace out of the way.

Deleted (32 files): app.js, responsive.css, landing.css, rules/app.js,
rules/styles.css, skills/app.js, the ten route index.html files, and the
root hands-on/ copy, which is byte-identical to public/hands-on/ -- the
one the build actually ships.

Moved to legacy/ (12 files): styles.css, full-guide/audit.css,
chapters.css, skills/styles.css, skills-review/styles.css,
skills-review/change-lens.css, and the skills-review/app.js module graph.
These are not dead. The Astro pages import them and the build fails
without them, which the plan had not accounted for. They go to legacy/
rather than src/ because check-tokens.mjs sweeps src, and these files are
full of raw hex and unnamed breakpoints: moving one into src/ should mean
migrating it to tokens in the same change, not adding a scan exclusion.
The prettier, stylelint, and eslint ignore lists that already named these
files at their old paths now name legacy/ instead.

verify.mjs no longer reads app.js. The 102 Portuguese strings were
extracted from its translations.pt object before deletion into
.agents/snapshots/full-guide-pt.json -- a legacy capture, not a snapshot
of the Astro build, so the assertion still compares against an
independent source. The brace-matching helper's assertion is replaced by
one that rejects an empty snapshot entry, without which trimming the
snapshot would make the presence check pass vacuously. Count stays at 84.

audit-ui.mjs reads the ten pages from dist/ and resolves Astro's
base-absolute hrefs against it.

Before deleting anything, rendered-text-diff was run across all ten
routes plus both Portuguese pages: every one at parity, 0 missing and 0
extra. That comparison is not repeatable once the legacy files are gone.
computed-style-diff on /full-guide/ stays at 32 differences, so the moves
are style-neutral.

Docs updated to match: README, AGENTS.md, GATES.md, the architecture
context, the operations guide's lab instructions, and the three skills
that told you to serve the vanilla site.

Publishing is not part of this commit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

hands-on/rules/styles.css

@@ -1 +0,0 @@
-:root{--paper:#f4f3ef;--ink:#173044;--muted:#687d8c;--blue:#5683a1;--gold:#efc86d;--line:#d5dde1}*{box-sizing:border-box}body{margin:0;min-width:320px;background:var(--paper);color:var(--ink);font-family:Arial,sans-serif}main{width:min(880px,calc(100% - 40px));margin:0 auto;padding:70px 0}header,.section-head{display:flex;justify-content:space-between;gap:30px;align-items:end}header{padding-bottom:50px;border-bottom:1px solid var(--line)}header span,.prompt-card>header span{font:10px monospace;letter-spacing:.08em}h1{margin:12px 0 0;font-size:clamp(48px,10vw,100px);letter-spacing:-.08em}header p{max-width:220px;color:var(--muted);line-height:1.5}section{padding-top:45px}h2{font-size:24px}.section-head>span{color:var(--blue);font:11px monospace}.rule-list,.prompt-grid{display:grid;gap:1px;background:var(--line);border:1px solid var(--line)}.rule{display:grid;grid-template-columns:1fr auto auto;gap:20px;padding:22px;background:var(--paper);align-items:center}.rule h3{margin:0 0 6px;font-size:17px}.rule p{margin:0;color:var(--muted);font-size:13px;line-height:1.45}.rule code{font:11px ui-monospace,monospace;color:var(--ink);background:var(--paper);padding:1px 5px;border:1px solid var(--line)}.rule-tag{font:10px monospace;letter-spacing:.08em;color:var(--muted);text-transform:uppercase}.toggle{appearance:none;width:44px;height:24px;border:1px solid var(--line);background:var(--paper);border-radius:12px;position:relative;cursor:pointer;transition:background .15s ease}.toggle::after{content:"";position:absolute;top:2px;left:2px;width:18px;height:18px;background:var(--ink);border-radius:50%;transition:transform .15s ease,background .15s ease}.toggle[aria-pressed="true"]{background:var(--blue);border-color:var(--blue)}.toggle[aria-pressed="true"]::after{transform:translateX(20px);background:var(--gold)}.prompt-grid{grid-template-columns:1fr 1fr;margin-top:18px}.prompt-card{background:var(--paper);padding:22px;display:flex;flex-direction:column;gap:14px}.prompt-card>header{display:flex;justify-content:space-between;align-items:end;padding-bottom:0;border-bottom:0}.prompt-card h3{margin:0;font-size:17px}.prompt-card pre{margin:0;font:12px ui-monospace,monospace;white-space:pre-wrap;word-break:break-word;color:var(--ink);background:var(--paper);border:1px solid var(--line);padding:14px;min-height:160px;line-height:1.5}#copy-btn{align-self:flex-start;appearance:none;border:1px solid var(--ink);background:var(--ink);color:var(--paper);font:11px monospace;letter-spacing:.08em;padding:9px 14px;cursor:pointer;text-transform:uppercase}#copy-btn[data-copied="true"]{background:var(--blue);border-color:var(--blue)}.lang-switch{display:flex;gap:1px;border:1px solid var(--line)}.lang-switch button{appearance:none;border:0;background:var(--paper);color:var(--muted);font:11px monospace;letter-spacing:.08em;padding:6px 10px;cursor:pointer;text-transform:uppercase}.lang-switch button[aria-pressed="true"]{background:var(--ink);color:var(--paper)}@media(max-width:720px){.prompt-grid{grid-template-columns:1fr}.rule{grid-template-columns:1fr}.rule-tag{display:none}}@media(max-width:560px){header{display:block}header p{margin-top:24px}.lang-switch{flex:1}.lang-switch button{flex:1}}