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/DirectoryPicker.vue

@@ -1,32 +1,32 @@
 <template>
-  <section class="flex flex-col gap-2 rounded-lg border border-zinc-800 bg-zinc-950/40 p-2">
+  <section class="flex flex-col gap-2 rounded-lg border border-border bg-surface-0/40 p-2">
     <header class="flex items-center gap-2">
       <button type="button" class="btn text-xs" :disabled="loading || parent === null" @click="load(parent ?? undefined)">
         ↑ {{ t('fs.up') }}
       </button>
-      <span class="min-w-0 flex-1 truncate font-mono text-xs text-zinc-400" :title="current">{{ current }}</span>
+      <span class="min-w-0 flex-1 truncate font-mono text-xs text-fg-muted" :title="current">{{ current }}</span>
       <button type="button" class="btn text-xs" @click="emit('close')">{{ t('common.cancel') }}</button>
     </header>
 
-    <p v-if="error" class="text-sm text-red-400">{{ error }}</p>
+    <p v-if="error" class="text-sm text-danger">{{ error }}</p>
 
     <ul class="flex max-h-60 flex-col gap-0.5 overflow-y-auto">
-      <li v-if="loading" class="px-2 py-1 text-xs text-zinc-500">{{ t('fs.loading') }}</li>
-      <li v-else-if="entries.length === 0" class="px-2 py-1 text-xs text-zinc-500">{{ t('fs.empty') }}</li>
+      <li v-if="loading" class="px-2 py-1 text-xs text-fg-subtle">{{ t('fs.loading') }}</li>
+      <li v-else-if="entries.length === 0" class="px-2 py-1 text-xs text-fg-subtle">{{ t('fs.empty') }}</li>
       <li v-for="e in entries" :key="e.path">
         <button
           type="button"
-          class="flex w-full items-center gap-2 rounded px-2 py-1 text-left text-sm text-zinc-200 hover:bg-zinc-800"
+          class="flex w-full items-center gap-2 rounded px-2 py-1 text-left text-sm text-fg hover:bg-surface-2"
           @click="load(e.path)"
         >
           <span class="flex-1 truncate font-mono">{{ e.name }}</span>
-          <span v-if="e.isRepo" class="badge bg-emerald-950 text-emerald-400">{{ t('fs.repoBadge') }}</span>
+          <span v-if="e.isRepo" class="badge bg-accent/15 text-accent">{{ t('fs.repoBadge') }}</span>
         </button>
       </li>
     </ul>
 
     <footer class="flex items-center gap-2">
-      <label class="flex items-center gap-1 text-xs text-zinc-400">
+      <label class="flex items-center gap-1 text-xs text-fg-muted">
         <input v-model="showHidden" type="checkbox" @change="load(current || undefined)" /> {{ t('fs.showHidden') }}
       </label>
       <button type="button" class="btn-primary ml-auto text-xs" :disabled="loading || current === ''" @click="emit('select', current)">