feat(theme-studio): add a real, exported :box face attribute

The mode-line box in the preview was hardcoded — it showed a box the generated theme couldn't actually produce, since build-theme.el never emitted :box. Made :box a real face attribute instead: a per-face box object (style line/raised/pressed, width, color) stored on UI and package faces, set from a "box" dropdown in both tables, rendered from the attribute everywhere (the mode-line bars, the package previews via ofs, the UI table preview cells), and exported through build-theme.el's --attrs as a proper :box plist (released/pressed → :style *-button; line → :line-width + optional :color). The hardcoded box is gone; mode-line and mode-line-inactive now default to the released-button box that is the Emacs default, so the preview and the export agree.

This also gives the package faces that genuinely use :box a way to represent it — the face audit found several (magit-branch-current/-remote-head, two flycheck list faces, the telega button family, ~15 slack button/dialog faces).

Tests: build-theme gains box-conversion + ui-box-emit ERT tests (24/24); the app-core deep-equal tests account for the new box slot; all 9 browser gates, 20 python, and 55 node tests stay green.

1 files changed, 3 insertions, 3 deletions

diff --git a/scripts/theme-studio/app-core.js b/scripts/theme-studio/app-core.js
index 91b9b1a9..0e3cfe49 100644
--- a/scripts/theme-studio/app-core.js
+++ b/scripts/theme-studio/app-core.js
@@ -9,13 +9,13 @@
 function nameToHex(n,palette){if(!n)return null;if(/^#/.test(n))return n;const p=palette.find(p=>p[1]===n);return p?p[0]:null;}
 
 // Seed the package-face map from the app inventory's per-face defaults.
-function buildPkgmap(apps,palette){const m={};for(const app in apps){m[app]={};for(const row of apps[app].faces){const face=row[0],d=row[2]||{};m[app][face]={fg:nameToHex(d.fg,palette),bg:nameToHex(d.bg,palette),bold:!!d.bold,italic:!!d.italic,underline:!!d.underline,strike:!!d.strike,inherit:d.inherit||null,height:d.height||1,source:'default'};}}return m;}
+function buildPkgmap(apps,palette){const m={};for(const app in apps){m[app]={};for(const row of apps[app].faces){const face=row[0],d=row[2]||{};m[app][face]={fg:nameToHex(d.fg,palette),bg:nameToHex(d.bg,palette),bold:!!d.bold,italic:!!d.italic,underline:!!d.underline,strike:!!d.strike,inherit:d.inherit||null,height:d.height||1,box:d.box||null,source:'default'};}}return m;}
 
 // The package faces worth exporting (anything seeded or user-touched), trimmed.
-function packagesForExport(map){const out={};for(const app in map){const faces={};for(const face in map[app]){const f=map[app][face];if(f.source==='default'||f.source==='user'||f.source==='cleared'){const o={fg:f.fg,bg:f.bg,bold:f.bold,italic:f.italic,underline:!!f.underline,strike:!!f.strike,inherit:f.inherit,source:f.source};if(f.height&&f.height!==1)o.height=f.height;faces[face]=o;}}if(Object.keys(faces).length)out[app]=faces;}return out;}
+function packagesForExport(map){const out={};for(const app in map){const faces={};for(const face in map[app]){const f=map[app][face];if(f.source==='default'||f.source==='user'||f.source==='cleared'){const o={fg:f.fg,bg:f.bg,bold:f.bold,italic:f.italic,underline:!!f.underline,strike:!!f.strike,inherit:f.inherit,source:f.source};if(f.height&&f.height!==1)o.height=f.height;if(f.box)o.box=f.box;faces[face]=o;}}if(Object.keys(faces).length)out[app]=faces;}return out;}
 
 // Merge an imported package block into a face map, filling missing fields.
-function mergePackagesInto(map,pkgs){if(!pkgs)return;for(const app in pkgs){if(!map[app])map[app]={};for(const face in pkgs[app]){const f=pkgs[app][face]||{};map[app][face]={fg:f.fg??null,bg:f.bg??null,bold:!!f.bold,italic:!!f.italic,underline:!!f.underline,strike:!!f.strike,inherit:f.inherit??null,height:f.height||1,source:f.source||'user'};}}}
+function mergePackagesInto(map,pkgs){if(!pkgs)return;for(const app in pkgs){if(!map[app])map[app]={};for(const face in pkgs[app]){const f=pkgs[app][face]||{};map[app][face]={fg:f.fg??null,bg:f.bg??null,bold:!!f.bold,italic:!!f.italic,underline:!!f.underline,strike:!!f.strike,inherit:f.inherit??null,height:f.height||1,box:f.box??null,source:f.source||'user'};}}}
 
 // Effective fg/bg for a package face, following its inherit chain. seen guards
 // against an inherit cycle (returns null rather than recursing forever).