revert(build): remove app build pipeline revamp (Nixpacks/MinIO/Trivy/registry GC)

Reverts commits 3eff38f and c379a23 and restores the previous Kaniko-only
build pipeline (runtime detection + per-runtime Dockerfile generation,
disk-based source upload).

Removed: Nixpacks Dockerfile generation, MinIO source storage (common/storage),
Bull build queue + Redis build state (common/redis, deployment.processor),
Trivy image scan (scan.service, deployment.vulnerabilitySummary), and daily
registry garbage collection (registry-gc). Nothing outside the build/deploy
path depended on these. Backend tsc + 105/106 tests green (the pre-existing
helm.service chartPath failure is unrelated); frontend tsc green.

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

frontend/src/components/vulnerability-badge.tsx

@@ -1,40 +0,0 @@
-import { ShieldCheck, ShieldAlert } from 'lucide-react';
-import type { VulnerabilitySummary } from '@/types';
-
-/**
- * Compact, report-only image-scan badge (Trivy). Renders nothing when there is
- * no scan data yet. Shows a green "clean" pill, or the count of the highest
- * severities found. Title carries the full per-severity breakdown.
- */
-export function VulnerabilityBadge({ summary }: { summary?: VulnerabilitySummary | null }) {
-  if (!summary) return null;
-
-  const { critical, high, medium, low, total } = summary;
-  const breakdown = `Critical ${critical} · High ${high} · Medium ${medium} · Low ${low}`;
-
-  if (total === 0) {
-    return (
-      <span
-        className="inline-flex items-center gap-1 text-[11px] font-medium text-green-700 bg-green-50 border border-green-200 rounded-full px-2 py-0.5"
-        title={breakdown}
-      >
-        <ShieldCheck className="w-3 h-3" /> 0 CVE
-      </span>
-    );
-  }
-
-  const severe = critical > 0 || high > 0;
-  const cls = severe
-    ? 'text-red-700 bg-red-50 border-red-200'
-    : 'text-amber-700 bg-amber-50 border-amber-200';
-  const label = severe ? `${critical}C / ${high}H` : `${medium}M / ${low}L`;
-
-  return (
-    <span
-      className={`inline-flex items-center gap-1 text-[11px] font-medium border rounded-full px-2 py-0.5 ${cls}`}
-      title={breakdown}
-    >
-      <ShieldAlert className="w-3 h-3" /> {label}
-    </span>
-  );
-}