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 in router/index.ts

Fixes Electron build failure caused by missing USE_DEXIE_DB export.

src/router/index.ts

@@ -73,6 +73,11 @@ const routes: Array<RouteRecordRaw> = [
     name: "contacts",
     component: () => import("../views/ContactsView.vue"),
   },
+  {
+    path: "/database-migration",
+    name: "database-migration",
+    component: () => import("../views/DatabaseMigration.vue"),
+  },
   {
     path: "/did/:did?",
     name: "did",
@@ -139,8 +144,9 @@ const routes: Array<RouteRecordRaw> = [
     component: () => import("../views/InviteOneView.vue"),
   },
   {
+    // optional because A) it could be a query param, and B) the page displays an input if things go wrong
     path: "/invite-one-accept/:jwt?",
-    name: "InviteOneAcceptView",
+    name: "invite-one-accept",
     component: () => import("../views/InviteOneAcceptView.vue"),
   },
   {
@@ -148,11 +154,6 @@ const routes: Array<RouteRecordRaw> = [
     name: "logs",
     component: () => import("../views/LogView.vue"),
   },
-  {
-    path: "/database-migration",
-    name: "database-migration",
-    component: () => import("../views/DatabaseMigration.vue"),
-  },
   {
     path: "/new-activity",
     name: "new-activity",