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, 12 insertions, 1 deletions

diff --git a/scripts/theme-studio/app-core.js b/scripts/theme-studio/app-core.js
index e74b0835e..85bfe7c63 100644
--- a/scripts/theme-studio/app-core.js
+++ b/scripts/theme-studio/app-core.js
@@ -537,4 +537,15 @@ function overflowNonDefault(cur,def,showInheritHeight){
   return false;
 }
 
-export { nameToHex, migrateLegacyFace, cssWeight, faceDecoration, boxCss, faceCss, normalizePkgFace, buildPkgmap, packagesForExport, mergePackagesInto, effResolve, resolveSyntaxFg, resolveUiAttr, dropdownRowTextColor, paletteOptionList, galleryModel, appViewKeysSorted, faceBoxNonDefaults, overflowNonDefault, stepViewIndex, spanNeighborHex, slugify, fgSetFor, floor, lMax, COVERED_FACES, columnsFromPalette, usedPaletteHexes, paletteUsages, regenColumn, rankByLightness, stepRepointPlan, sortColumns, sortColumnMembers, groundRoleOfEntry, groundColumnMembersFromPalette, clearPalettePlan, deletePaletteColumnPlan, areAllLocked, lockToggleLabel, toggleLockSet };
+// Compose an element-hover tooltip: the face's docstring on top, the existing
+// hover text (e.g. the bare face name) below it, separated by a blank line. A
+// missing doc or base collapses to whichever is present; missing both yields ''.
+// Keyed lookups (FACE_DOCS[face], SYNTAX_DOCS[kind]) supply DOC; BASE is
+// whatever title the element carried before.
+function composeHoverTitle(doc,base){
+  doc=doc||''; base=base||'';
+  if(doc&&base)return doc+'\n\n'+base;
+  return doc||base;
+}
+
+export { nameToHex, migrateLegacyFace, cssWeight, faceDecoration, boxCss, faceCss, composeHoverTitle, normalizePkgFace, buildPkgmap, packagesForExport, mergePackagesInto, effResolve, resolveSyntaxFg, resolveUiAttr, dropdownRowTextColor, paletteOptionList, galleryModel, appViewKeysSorted, faceBoxNonDefaults, overflowNonDefault, stepViewIndex, spanNeighborHex, slugify, fgSetFor, floor, lMax, COVERED_FACES, columnsFromPalette, usedPaletteHexes, paletteUsages, regenColumn, rankByLightness, stepRepointPlan, sortColumns, sortColumnMembers, groundRoleOfEntry, groundColumnMembersFromPalette, clearPalettePlan, deletePaletteColumnPlan, areAllLocked, lockToggleLabel, toggleLockSet };