[refactor] Enforce enum type safety by removing type assertions (#5315)

Remove type assertions (as ManagerChannel) that bypass TypeScript's type
checking and replace with explicit Record typing. This ensures invalid
enum values are caught at compile time rather than runtime.

- Replace type assertions with Record<string, ManagerChannel> typing
- Remove manual casting that bypassed TypeScript validation
- Ensure enum values are validated during compilation

src/components/dialog/content/manager/PackVersionSelectorPopover.vue

@@ -110,8 +110,8 @@ const SelectedVersionValues = {
 }
 
 const ManagerChannelValues: Record<string, ManagerChannel> = {
-  DEFAULT: 'default', // ✅ Valid - will compile
+  DEFAULT: 'default',
-  DEV: 'dev' // ✅ Valid - will compile
+  DEV: 'dev'
 }
 
 const ManagerDatabaseSourceValues: Record<string, ManagerDatabaseSource> = {