Refactor character affiliations to singular form

- Updated character data structure to replace 'affiliations' and 'frAffiliations' with 'affiliation' and 'frAffiliation'.
- Modified related functions and components to accommodate the new structure.
- Adjusted database schema and server-side logic to reflect the changes in character affiliation handling.
- Ensured all references in the UI components and data import/export scripts are updated accordingly.

drizzle/meta/_journal.json

@@ -22,6 +22,13 @@
       "when": 1775950314114,
       "tag": "0002_old_earthquake",
       "breakpoints": true
+    },
+    {
+      "idx": 3,
+      "version": "6",
+      "when": 1776195681488,
+      "tag": "0003_mixed_ben_grimm",
+      "breakpoints": true
     }
   ]
 }