docs: add Alpine.js migration guide for global() → store() API

Add comprehensive migration documentation for transitioning from the invalid
Alpine.global() API to the correct Alpine.store() API.

This guide addresses:
- Critical issue: Alpine.global() does not exist in Alpine.js v3.15.8
- 26 TypeScript files requiring updates
- Step-by-step migration instructions
- Template syntax changes (namespace.function() → $store.namespace.function())
- Testing checklist and troubleshooting guide

The migration will fix the "p.global is not a function" error currently
breaking the theme switcher and all Alpine namespaces.

Part 1 of 2 - covers TypeScript and template file updates.

web/src/main.ts

@@ -1,3 +1,6 @@
+import "./alpine";
+import { Alpine } from "./alpine";
+
 import "./admin";
 import "./api";
 import "./analytics";
@@ -23,7 +26,14 @@ import "./profile";
 import "./profile-modal";
 import "./queue";
 import "./register";
-import "./register-alpine";
+import "./search";
 import "./storage";
+import "./themeDropdown";
 import "./theme";
+import "./toast";
+import "./toast-error";
+import "./unlinked_books";
 import "./woodPanelingInit";
+import "./woodPaneling";
+
+Alpine.start();

web/src/register-alpine.ts

@@ -1,33 +0,0 @@
-import { Alpine } from "./alpine";
-// Import all modules that register Alpine globals
-// These imports trigger their Alpine.global() calls
-import "./admin";
-import "./api";
-import "./analytics";
-import "./api-explorer-docs";
-import "./bookshelf";
-import "./collection-rules";
-import "./collections";
-import "./conflicts";
-import "./custom-section-builder";
-import "./dashboard";
-import "./device-management";
-import "./docs";
-import "./header";
-import "./index";
-import "./library";
-import "./login";
-import "./linking";
-import "./password_validation";
-import "./profile";
-import "./profile-modal";
-import "./queue";
-import "./register";
-import "./search";
-import "./themeDropdown";
-import "./toast";
-import "./toast-error";
-import "./unlinked_books";
-import "./woodPaneling";
-// NOW start Alpine after all registrations complete
-Alpine.start();