NAS syndication adapter (feature-flagged off): push banner/text to Network Ad Space, reconcile delivery into unified credit pool

- nas.js: direct-MySQL writer mirroring CTB's proven payments+sponsorads path (approved:1, pid 1/2, catid 5, remaining counts DOWN)
- Create-time push for banner/text; pause/resume mirrors to NAS deactivate/topUp
- reconcileNas() 5-min loop: reads served, charges delta credits to the shared budget, stops NAS ad when budget dry
- Campaign row shows IAP + '+N net' network views (differentiated stats)
- Inert unless NAS_DB_* env is set; zero prod impact until enabled
- Also: rename Inbox sub-tab to 'Inbox Ads'

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

db.js

@@ -108,6 +108,8 @@ async function bootstrap() {
   await alterSafe('ALTER TABLE campaigns ADD COLUMN cta_label VARCHAR(40) NULL');
   await alterSafe('ALTER TABLE campaigns ADD COLUMN width INT NULL');   // banner size (IAB) → also NAS width
   await alterSafe('ALTER TABLE campaigns ADD COLUMN height INT NULL');  // banner size (IAB) → also NAS height
+  await alterSafe('ALTER TABLE campaigns ADD COLUMN nas_ad_id INT NULL');          // syndicated NAS sponsorads.ID
+  await alterSafe('ALTER TABLE campaigns ADD COLUMN nas_served INT NOT NULL DEFAULT 0'); // NAS impressions already reconciled into spend
   await q(`CREATE TABLE IF NOT EXISTS burns (
     id VARCHAR(32) PRIMARY KEY,
     member_id INT NOT NULL,