HS: Group 11 misc — toggle-var-cycle, closest-to, tailwind class, toggle timing (+3 tests)

- parser: `toggle $var between v1 and v2 ...` → `(toggle-var-cycle $var (v1 v2 ...))`
- compiler: emit `(hs-toggle-var-cycle! win var-name values)` for new AST node
- runtime: `hs-toggle-var-cycle!` cycles through a list of values on a variable
- parser: `closest .sel to .target` / `closest #id to .target` / `closest sel to .target`
  now consumes the `to` keyword and parses the target expr instead of defaulting to beingTold
- tokenizer: `read-class-name` handles backslash escapes and allows `(`, `)`, `&`
  chars so Tailwind classes like `group-[:nth-of-type(3)_&]:block` tokenize correctly
- platform.py: `domListen` drives async result via `_driveAsync` after `cekCall`
- test: fixed-time toggle asserts `.foo` IS present after click (toggle started, 10ms window open)
- generate-sx-tests.py: aligned MANUAL_TEST_BODIES for timed toggle with corrected assertion

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/hs-run-filtered.js

@@ -577,7 +577,7 @@ K.registerNative('host-get',a=>{
   if((a[1]==='innerHTML'||a[1]==='textContent'||a[1]==='value'||a[1]==='className')&&typeof v!=='string')v=String(v!=null?v:'');
   return v;
 });
-K.registerNative('host-set!',a=>{if(a[0]!=null){const v=a[2];if(a[1]==='_hs_null_error'||a[1]==='_hs_last_query_sel')process.stderr.write(`[HS-DBG] host-set! ${a[1]}=${JSON.stringify(v)}\n`); if(a[1]==='innerHTML'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0]._setInnerHTML(s);a[0][a[1]]=a[0].innerHTML;} else if(a[1]==='textContent'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0].textContent=s;a[0].innerHTML=s;for(const c of a[0].children){c.parentElement=null;c.parentNode=null;}a[0].children=[];a[0].childNodes=[];} else{a[0][a[1]]=v;}} return a[2];});
+K.registerNative('host-set!',a=>{if(a[0]!=null){const v=a[2]; if(a[1]==='innerHTML'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0]._setInnerHTML(s);a[0][a[1]]=a[0].innerHTML;} else if(a[1]==='textContent'&&a[0] instanceof El){const s=v===null?'null':v===undefined?'':String(v);a[0].textContent=s;a[0].innerHTML=s;for(const c of a[0].children){c.parentElement=null;c.parentNode=null;}a[0].children=[];a[0].childNodes=[];} else{a[0][a[1]]=v;}} return a[2];});
 K.registerNative('host-call',a=>{if(_testDeadline&&Date.now()>_testDeadline)throw new Error('TIMEOUT: wall clock exceeded');const[o,m,...r]=a;if(o==null){const f=globalThis[m];return typeof f==='function'?f.apply(null,r):null;}if(o&&typeof o[m]==='function'){try{const v=o[m].apply(o,r);return v===undefined?null:v;}catch(e){return null;}}return null;});
 K.registerNative('host-call-fn',a=>{const[fn,argList]=a;if(typeof fn!=='function'&&!(fn&&fn.__sx_handle!==undefined))return null;const callArgs=(argList&&argList._type==='list'&&argList.items)?Array.from(argList.items):(Array.isArray(argList)?argList:[]);if(fn&&fn.__sx_handle!==undefined)return K.callFn(fn,callArgs);function sxToJs(v){if(v&&v._type==='list'&&v.items)return Array.from(v.items).map(sxToJs);return v;}try{const v=fn.apply(null,callArgs.map(sxToJs));return v===undefined?null:v;}catch(e){return null;}});
 K.registerNative('host-new',a=>{const C=typeof a[0]==='string'?globalThis[a[0]]:a[0];return typeof C==='function'?new C(...a.slice(1)):null;});