fix: VPS fresh-DB bootstrap — sync OPENAI_API_KEY from env to DB at startup + show countdown before first cycle

- main.py startup: if DB has no openai_api_key but OPENAI_API_KEY env var is set, auto-save it so cycle trigger returns 200 instead of 400
- Config.tsx: move NextRunCountdown outside cs?.last_cycle block so it renders even when no cycle has run yet

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/Config.tsx

@@ -720,7 +720,7 @@ export default function Config() {
         <RiskProfilesCard />
 
         {cs?.last_cycle && (
-          <div className="card bg-dark-700/50 mb-4 text-xs space-y-2">
+          <div className="card bg-dark-700/50 mb-2 text-xs space-y-2">
             <div className="flex items-center gap-4 flex-wrap">
               <span className="text-slate-500">Dernier cycle :</span>
               <span className="text-slate-300">{cs.last_cycle.started_at?.slice(0, 16)} UTC</span>
@@ -732,9 +732,11 @@ export default function Config() {
               <span className="text-slate-500">Géo: {cs.last_cycle.geo_score}</span>
               <span className="text-slate-500 capitalize">{cs.last_cycle.dominant_regime}</span>
             </div>
-            {cs.enabled && cs.next_run_at && !cs.running && (
-              <NextRunCountdown nextRunAt={cs.next_run_at} />
-            )}
+          </div>
+        )}
+        {cs?.enabled && cs?.next_run_at && !cs?.running && (
+          <div className="card bg-dark-700/50 mb-4 text-xs">
+            <NextRunCountdown nextRunAt={cs.next_run_at} />
           </div>
         )}