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.