One companion study guide per series; v2.9.8

- Second series gets its own guide (Resources page card, download page, admin fields)
- When a series ends (scheduled or manual) its guide moves onto its Finished Book, which shows a guide button; the main series' guide is cleared unless the launch supplies a new one
- Lane B launch schedule can supply the incoming series' guide
- Download lookup covers second-series and finished-book guides; guide URLs are sanitized on save and on use

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "2.9.7",
+  "version": "2.9.8",
   "type": "module",
   "scripts": {
     "dev": "vite",