Refactor to generic ERP base

Remove influencer-specific features (campaigns, TikTok, gifts, shadow ledger,
contracts, briefings) and consolidate into a clean ERP foundation with core
bookkeeping, invoicing, receipts, tax reporting, and calendar functionality.
Reorganize database migrations into a clean numbered sequence.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/manifest.json

@@ -1,7 +1,7 @@
 {
-  "name": "Influencer Assistant",
-  "short_name": "InfluencerAI",
-  "description": "Ekonomihantering för svenska influencers",
+  "name": "ERP Base",
+  "short_name": "ERPBase",
+  "description": "Ekonomihantering",
   "start_url": "/",
   "display": "standalone",
   "background_color": "#ffffff",

public/sw.js

@@ -32,7 +32,7 @@ self.addEventListener('push', (event) => {
   }
 
   event.waitUntil(
-    self.registration.showNotification(title || 'Influencer Assistant', options)
+    self.registration.showNotification(title || 'Ekonomi', options)
   )
 })