feat: extend weekly-slot intervals from 18 to 23 (#1345)

## Summary
- Add `WEEKLY_SLOT_19` through `WEEKLY_SLOT_23` to JOB_INTERVALS enum (5
empty slots for future growth)

## Related PRs
- adobe/spacecat-audit-worker — `feat/extend-geo-brand-splits-to-23`
- adobe/spacecat-api-service — `feat/extend-geo-brand-splits-to-23`
- adobe/spacecat-infrastructure — `feat/extend-geo-brand-splits-to-23`

## Test plan
- [x] Linting clean

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: dzehnder

packages/spacecat-shared-data-access/src/models/configuration/configuration.model.js

@@ -49,9 +49,9 @@ class Configuration {
     FORTNIGHTLY_SUNDAY: 'fortnightly-sunday',
     MONTHLY: 'monthly',
     QUARTERLY: 'quarterly',
-    // Staggered weekly slots for split audits (e.g. geo-brand-presence-free-1..18)
+    // Staggered weekly slots for split audits (e.g. geo-brand-presence-free-1..23)
     ...Object.fromEntries(
-      Array.from({ length: 18 }, (_, i) => [`WEEKLY_SLOT_${i + 1}`, `weekly-slot-${i + 1}`]),
+      Array.from({ length: 23 }, (_, i) => [`WEEKLY_SLOT_${i + 1}`, `weekly-slot-${i + 1}`]),
     ),
   };