Add cookie banner versioning with JSONB snapshots

Introduce append-only cookie_banner_versions table with a JSONB
snapshot of consent-relevant configuration (privacy policy URL,
consent mode, expiry, categories and their cookies). Each version
has its own state (DRAFT/PUBLISHED) separate from the banner
lifecycle.

Replace the banner state enum (DRAFT/PUBLISHED/DISABLED) with a
simpler ACTIVE/INACTIVE toggle. Link consent records to the
specific published version the visitor accepted.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/coredata/cookie_banner.go

@@ -118,7 +118,7 @@ LIMIT 1;
 	return nil
 }
 
-func (b *CookieBanner) LoadPublishedByID(
+func (b *CookieBanner) LoadActiveByID(
 	ctx context.Context,
 	conn pg.Querier,
 	bannerID gid.GID,
@@ -139,7 +139,7 @@ FROM
 	cookie_banners
 WHERE
 	id = @banner_id
-	AND state = 'PUBLISHED'
+	AND state = 'ACTIVE'
 LIMIT 1;
 `