feat(web): refonte visuelle « Emerald » (thème clair/sombre, polices, tokens)

Adopte le langage visuel du design system Emerald dans l'IDE web :
neutres zinc + accent emerald, polices auto-hébergées Inter + JetBrains
Mono, radii/pills mono, points de statut, motif terminal, halo/grain.
Refonte purement visuelle et additive (layout, routing, stores, protocole
inchangés).

- style.css : défauts sombres dans @theme + override clair sous
  html[data-theme=light] ; accent scindé (bright #34d399 / solid #059669 /
  hover) ; tokens border-soft/info/warn/danger/coffee ; idiomes globaux
  (focus/selection accent, scrollbars fines, jl-pulse/jl-blink, classes
  .chip/.status/.eyebrow/.label-mono/.caret/.halo/.grain, .btn*/.badge pill).
- lib/theme.ts : singleton themeMode/resolvedTheme (dark/light/system,
  persistedRef arb.theme) + application dataset.theme/metas ; script
  anti-FOUC inline dans index.html ; toggle ActivityBar + Réglages.
- Thèmes Monaco + xterm dark/light réactifs (palette ANSI + coloration
  syntaxique) ; fonts.ready + remeasureFonts pour l'alignement des glyphes.
- status-tokens : tons sémantiques tokenisés ; balayage des ~340 couleurs
  Tailwind brutes vers les tokens sur tout components/* et views/*
  (exceptions assumées commentées).
- GroupSummary.color exploité : icône de groupe teintée + ColorSwatchPicker
  (lib/group-colors.ts) dans les modals de groupe.
- Polices via @fontsource-variable/{inter,jetbrains-mono} (offline).

packages/web/src/components/workspace/DiffViewer.vue

@@ -1,27 +1,27 @@
 <template>
   <div class="flex h-full flex-col">
-    <p v-if="loading" class="p-3 text-xs text-zinc-500">{{ t('fs.loading') }}</p>
-    <p v-else-if="error" class="p-3 text-xs text-rose-400">{{ error }}</p>
-    <p v-else-if="binary" class="p-3 text-xs text-zinc-500">{{ t('diff.binary') }}</p>
-    <p v-else-if="tooLarge" class="p-3 text-xs text-amber-500">{{ t('diff.tooLarge') }}</p>
-    <p v-else-if="parsed.hunks.length === 0" class="p-3 text-xs text-zinc-500">{{ t('diff.noChanges') }}</p>
+    <p v-if="loading" class="p-3 text-xs text-fg-subtle">{{ t('fs.loading') }}</p>
+    <p v-else-if="error" class="p-3 text-xs text-danger">{{ error }}</p>
+    <p v-else-if="binary" class="p-3 text-xs text-fg-subtle">{{ t('diff.binary') }}</p>
+    <p v-else-if="tooLarge" class="p-3 text-xs text-warn">{{ t('diff.tooLarge') }}</p>
+    <p v-else-if="parsed.hunks.length === 0" class="p-3 text-xs text-fg-subtle">{{ t('diff.noChanges') }}</p>
     <div v-else class="min-h-0 flex-1 overflow-auto">
-      <div class="flex items-center gap-3 border-b border-zinc-800 px-3 py-1 text-[11px] text-zinc-500">
-        <span class="text-emerald-500">+{{ parsed.additions }}</span>
-        <span class="text-rose-500">−{{ parsed.deletions }}</span>
-        <span v-if="staged" class="rounded bg-emerald-950 px-1 text-emerald-400">{{ t('git.staged') }}</span>
+      <div class="flex items-center gap-3 border-b border-border px-3 py-1 text-[11px] text-fg-subtle">
+        <span class="text-accent">+{{ parsed.additions }}</span>
+        <span class="text-danger">−{{ parsed.deletions }}</span>
+        <span v-if="staged" class="rounded bg-accent/15 px-1 text-accent">{{ t('git.staged') }}</span>
       </div>
       <table class="w-full border-collapse font-mono text-xs leading-5">
         <tbody>
           <template v-for="(h, hi) in parsed.hunks" :key="hi">
-            <tr class="bg-zinc-900/60 text-sky-300/80">
-              <td class="select-none px-2 text-right text-zinc-700" />
-              <td class="select-none px-2 text-right text-zinc-700" />
+            <tr class="bg-surface-1/60 text-info/80">
+              <td class="select-none px-2 text-right text-fg-subtle" />
+              <td class="select-none px-2 text-right text-fg-subtle" />
               <td class="whitespace-pre px-2">{{ h.header }}</td>
             </tr>
             <tr v-for="(l, li) in h.lines" :key="`${hi}-${li}`" :class="rowClass(l.type)">
-              <td class="w-10 select-none px-2 text-right text-zinc-600">{{ l.oldLine ?? '' }}</td>
-              <td class="w-10 select-none px-2 text-right text-zinc-600">{{ l.newLine ?? '' }}</td>
+              <td class="w-10 select-none px-2 text-right text-fg-subtle">{{ l.oldLine ?? '' }}</td>
+              <td class="w-10 select-none px-2 text-right text-fg-subtle">{{ l.newLine ?? '' }}</td>
               <td class="whitespace-pre px-2">{{ marker(l.type) }}{{ l.content }}</td>
             </tr>
           </template>
@@ -66,9 +66,9 @@ async function load(): Promise<void> {
 watch(() => [props.repoId, props.wt, props.file, props.staged, props.version], load, { immediate: true });
 
 function rowClass(type: DiffLineType): string {
-  if (type === 'add') return 'bg-emerald-950/40 text-emerald-200';
-  if (type === 'del') return 'bg-rose-950/40 text-rose-200';
-  return 'text-zinc-300';
+  if (type === 'add') return 'diff-add';
+  if (type === 'del') return 'diff-del';
+  return 'diff-ctx';
 }
 function marker(type: DiffLineType): string {
   return type === 'add' ? '+' : type === 'del' ? '-' : ' ';