Fix: "Modelle finden" bevorzugt faehigste passende Modelle (kein Downgrade) + Rollen-Farben zentral

- discover.rank_runnable: rankt jetzt fit-level > params_b(desc) > downloads -> fuer die
  128GB-Box wird das faehigste passende (MoE-)Modell empfohlen statt kleiner Populaer-Modelle.
  Top-4-Anzeige nutzt dasselbe Ranking.
- maintenance.model_upgrades: schlaegt KEIN Downgrade mehr vor (rec.params_b >= installiert*0.95).
  Behebt: fast 35B-A3B -> 4B wurde faelschlich als Upgrade angeboten.
- Frontend: Rollen-Farb-Mapping zentralisiert in ModelBadges (ROLE_TONE/roleTone);
  Cockpit/RolesCard/ActiveModelsCard nutzen es statt eigener Duplikate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/models/Cockpit.tsx

@@ -6,7 +6,7 @@ import { useDialog } from "@/lib/useDialog"
 import { CapsChips } from "@/components/CapsChips"
 import { cn } from "@/lib/utils"
 import { fmtSize, fmtCtx } from "@/lib/format"
-import { getBrandInfo, ROLES } from "@/components/models/ModelBadges"
+import { getBrandInfo, ROLES, roleTone } from "@/components/models/ModelBadges"
 import { SpecDraftModal } from "@/components/models/SpecDraftModal"
 
 export function Cockpit() {
@@ -611,12 +611,7 @@ export function Cockpit() {
               >
                 <div className="flex items-center justify-between">
                   <span className={cn("text-[9px] font-bold uppercase tracking-wider font-mono px-1.5 py-0.5 rounded border",
-                    role === "fast" ? "bg-cyan-500/10 text-cyan-400 border-cyan-500/20" :
-                    role === "heavy" ? "bg-amber-500/10 text-amber-400 border-amber-500/20" :
-                    role === "coder" ? "bg-violet-500/10 text-violet-400 border-violet-500/20" :
-                    role === "vision" ? "bg-pink-500/10 text-pink-400 border-pink-500/20" :
-                    "bg-teal-500/10 text-teal-400 border-teal-500/20"
-                  )}>{role}</span>
+                    roleTone(role))}>{role}</span>
                   {isWarm && <span className="h-1.5 w-1.5 rounded-full bg-emerald-400 animate-pulse" />}
                 </div>