Fix: stamp semana_iniciada_em when campaign first transitions to 'rodando'

Previously, setCampaignStatus did not set semana_iniciada_em, causing
escalateWeeklyLimits to bail early (if (!campaign.semana_iniciada_em) continue).
Now when a campaign transitions to 'rodando' for the first time, semana_iniciada_em
is set to datetime('now'). Subsequent rodando transitions leave it unchanged
(using COALESCE to preserve first-run timestamp).

Regression tests confirm:
- First transition to 'rodando' stamps semana_iniciada_em
- Subsequent transitions do not reset the timestamp
- resumeCampaign continues to work correctly (pause/resume cycle)
- All 105 tests pass

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/outreach/campaign-store.mjs

@@ -44,9 +44,18 @@ export function listVariants(db, campaignId) {
 // status: 'rascunho' -> 'rodando' -> 'pausado' <-> 'rodando' -> 'concluido'.
 // pause_reason so fica setado quando o novo status e 'pausado'.
 export function setCampaignStatus(db, campaignId, status, pauseReason = null) {
-  db.prepare(
-    `UPDATE outreach_campaigns SET status = ?, pause_reason = ?, updated_at = datetime('now') WHERE id = ?`
-  ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  if (status === 'rodando') {
+    // When transitioning to 'rodando', stamp semana_iniciada_em only on first run (if currently NULL)
+    db.prepare(
+      `UPDATE outreach_campaigns
+       SET status = ?, pause_reason = ?, semana_iniciada_em = COALESCE(semana_iniciada_em, datetime('now')), updated_at = datetime('now')
+       WHERE id = ?`
+    ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  } else {
+    db.prepare(
+      `UPDATE outreach_campaigns SET status = ?, pause_reason = ?, updated_at = datetime('now') WHERE id = ?`
+    ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  }
   return getCampaign(db, campaignId);
 }