Banner ads: required IAB size picker (width/height stored, shown in row, maps to NAS)

Also lands dormant server-side scaffolding for video ads (type, tiers, validation) — not yet exposed in UI.

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

db.js

@@ -105,6 +105,8 @@ async function bootstrap() {
   // solo message bodies are sanitized rich text; TEXT gives them room
   await alterSafe('ALTER TABLE campaigns MODIFY body TEXT NULL');
   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 q(`CREATE TABLE IF NOT EXISTS burns (
     id VARCHAR(32) PRIMARY KEY,
     member_id INT NOT NULL,