Fix InviteOneAcceptView migration fence; remove USE_DEXIE_DB dependency

- Remove USE_DEXIE_DB import from app.ts constants
- Update InviteOneAcceptView to use PlatformServiceMixin pattern
- Remove legacy Dexie database access code
- Move WORKER_ONLY_DATABASE_IMPLEMENTATION.md to doc/ directory
- Remerge changes from master router/index.ts

Fixes Electron build failure caused by missing USE_DEXIE_DB export.

src/router/index.ts

@@ -1,6 +1,7 @@
 import {
   createRouter,
   createWebHistory,
+  createMemoryHistory,
   RouteLocationNormalized,
   RouteRecordRaw,
 } from "vue-router";
@@ -281,9 +282,14 @@ const routes: Array<RouteRecordRaw> = [
   },
 ];
 
-const initialPath = window.location.pathname;
+const isElectron = window.location.protocol === "file:";
+const initialPath = isElectron
+  ? window.location.pathname.split("/dist-electron/www/")[1] || "/"
+  : window.location.pathname;
 
-const history = createWebHistory("/"); // Add base path for web apps
+const history = isElectron
+  ? createMemoryHistory() // Memory history for Electron
+  : createWebHistory("/"); // Add base path for web apps
 
 /** @type {*} */
 const router = createRouter({