feat(theme-studio): show face docstrings in element hovers

Each table row's category cell now shows the face's Emacs docstring on hover, on top of whatever the cell showed before. The package cell keeps the face name underneath. The syntax and UI cells had no prior tooltip, so they show just the docstring. The label-span hints are left alone.

I added face-docs-dump.el, which emits face-docs.json from a live Emacs: a face-name to first-doc-line map for the UI and package tables, and a category to doc map for the syntax table. The category to font-lock-face mapping is read from build-theme.el's own map, so it isn't copied a third time. generate.py inlines both maps. A pure composeHoverTitle helper composes the tooltip, covered by Node, Python, and a new browser gate.

1 files changed, 4 insertions, 3 deletions

diff --git a/scripts/theme-studio/app.js b/scripts/theme-studio/app.js
index 7f41741a2..f6e4cd2cd 100644
--- a/scripts/theme-studio/app.js
+++ b/scripts/theme-studio/app.js
@@ -1,5 +1,6 @@
 const SAMPLES=SAMPLES_J, CATS=CATS_J, UI_FACES=UIFACES_J, APPS=APPS_J;
 const COLOR_NAMES=COLOR_NAMES_J;
+const FACE_DOCS=FACE_DOCS_J, SYNTAX_DOCS=SYNTAX_DOCS_J; // face/category -> docstring first line, for element hovers
 let MAP=MAP_J, PALETTE=PALETTE_J, SYNTAX=SYNTAX_J, UIMAP=UIMAP_J;
 let LOCKED=new Set(LOCKS_J);   // rows whose choice is decided (controls disabled, skipped by erase/reset batch actions)
 const DELTAE_MIN=0.02; // OKLab ΔE below this = colors too close to tell apart (perceptual-metrics spec)
@@ -297,7 +298,7 @@ function buildTable(){
     const exp=mkExpander(syntaxFace(kind),tableColCount('legtable'),()=>{styleEx();renderCode();},{showInheritHeight:true,inheritOptions:[''].concat(BASE_INHERITS),defaultHex:rowFg(),ndCheck:()=>overflowNonDefault(syntaxFace(kind),DEFAULT_SYNTAX[kind],true)});
     exp.detail.dataset.detailFor=kind;
     const lkTd=mkLockCell(kind,[dd,bgd,...stCtls,boxCtl,...exp.locks]);
-    const c2=document.createElement('td');c2.className='cat';c2.appendChild(exp.btn);
+    const c2=document.createElement('td');c2.className='cat';c2.title=composeHoverTitle(SYNTAX_DOCS[kind],c2.title);c2.appendChild(exp.btn);
     const c2lbl=document.createElement('span');c2lbl.textContent=' '+label;c2lbl.style.cursor='pointer';c2lbl.title='flash this category in the code';c2lbl.onclick=()=>flashTokens(kind);c2.appendChild(c2lbl);
     tr.appendChild(c2);tr.appendChild(lkTd);tr.appendChild(c0);tr.appendChild(cB);tr.appendChild(stTd);tr.appendChild(cX);tr.appendChild(crTd);tr.appendChild(exTd);
     tb.appendChild(tr);tb.appendChild(exp.detail);}
@@ -614,7 +615,7 @@ function buildPkgTable(){
       {fg:nameToHex(def.fg,PALETTE),bg:nameToHex(def.bg,PALETTE),weight:def.weight,slant:def.slant,underline:def.underline,strike:def.strike,inherit:def.inherit,height:def.height,box:def.box});
     const exp=mkExpander(f,tableColCount('pkgtable'),()=>{f.source='user';pkgChanged();},{defaultHex:effFg(pkgEffFg(app,face)),ndCheck:()=>overflowNonDefault(f,def,false)});
     exp.detail.dataset.detailFor=face;
-    const c0=document.createElement('td');c0.className='cat';c0.title=face;c0.appendChild(exp.btn);
+    const c0=document.createElement('td');c0.className='cat';c0.title=composeHoverTitle(FACE_DOCS[face],face);c0.appendChild(exp.btn);
     const c0lbl=document.createElement('span');c0lbl.textContent=' '+label;c0lbl.style.cursor='pointer';c0lbl.onclick=()=>flashPkgPreview(face);c0.appendChild(c0lbl);
     const fgd=mkColorDropdown(ddList(f.fg||''),f.fg||'',h=>{f.fg=h||null;f.source='user';pkgChanged();},{compact:true,defaultHex:effFg(pkgEffFg(app,face))}),
           bgd=mkColorDropdown(ddList(f.bg||''),f.bg||'',h=>{f.bg=h||null;f.source='user';pkgChanged();},{compact:true,defaultHex:effBg(pkgEffBg(app,face))});
@@ -709,7 +710,7 @@ function buildUITable(){
     const tr=document.createElement('tr');tr.dataset.face=face;
     const exp=mkExpander(UIMAP[face],tableColCount('uitable'),()=>{paintUI(face);buildMockFrame();},{showInheritHeight:true,inheritOptions:[''].concat(BASE_INHERITS),defaultHex:effFg(UIMAP[face].fg),ndCheck:()=>overflowNonDefault(UIMAP[face],DEFAULT_UIMAP[face],true)});
     exp.detail.dataset.detailFor=face;
-    const c0=document.createElement('td');c0.className='cat';c0.appendChild(exp.btn);
+    const c0=document.createElement('td');c0.className='cat';c0.title=composeHoverTitle(FACE_DOCS[face],c0.title);c0.appendChild(exp.btn);
     const c0lbl=document.createElement('span');c0lbl.textContent=' '+label;c0lbl.style.cursor='pointer';c0lbl.title='flash this face in the live preview';c0lbl.onclick=()=>flashUiPreview(face);c0.appendChild(c0lbl);
     const fgSel=uiSelect(face,'fg'),bgSel=uiSelect(face,'bg');
     const cF=document.createElement('td');cF.appendChild(fgSel);