feat: move database migration link from account view to start view

- Remove database migration link from AccountViewView.vue
- Add new "Database Tools" section to StartView.vue
- Improve user flow by making database tools accessible from start page
- Maintain consistent styling and functionality
- Clean up account view to focus on account-specific settings

The database migration feature is now logically grouped with other
identity-related operations and more discoverable for users.

src/views/ImportAccountView.vue

@@ -88,17 +88,9 @@ import { Router } from "vue-router";
 
 import { AppString, NotificationIface, USE_DEXIE_DB } from "../constants/app";
 import * as databaseUtil from "../db/databaseUtil";
-import {
-  accountsDBPromise,
-  retrieveSettingsForActiveAccount,
-} from "../db/index";
-import {
-  DEFAULT_ROOT_DERIVATION_PATH,
-  deriveAddress,
-  newIdentifier,
-} from "../libs/crypto";
-import { retrieveAccountCount, saveNewIdentity } from "../libs/util";
-import { PlatformServiceFactory } from "@/services/PlatformServiceFactory";
+import { retrieveSettingsForActiveAccount } from "../db/index";
+import { DEFAULT_ROOT_DERIVATION_PATH } from "../libs/crypto";
+import { retrieveAccountCount, importFromMnemonic } from "../libs/util";
 import { logger } from "../utils/logger";
 
 @Component({
@@ -115,12 +107,9 @@ export default class ImportAccountView extends Vue {
   $router!: Router;
 
   apiServer = "";
-  address = "";
   derivationPath = DEFAULT_ROOT_DERIVATION_PATH;
   mnemonic = "";
   numAccounts = 0;
-  privateHex = "";
-  publicHex = "";
   showAdvanced = false;
   shouldErase = false;
 
@@ -143,33 +132,16 @@ export default class ImportAccountView extends Vue {
   }
 
   public async fromMnemonic() {
-    const mne: string = this.mnemonic.trim().toLowerCase();
     try {
-      [this.address, this.privateHex, this.publicHex] = deriveAddress(
-        mne,
+      await importFromMnemonic(
+        this.mnemonic,
         this.derivationPath,
+        this.shouldErase,
       );
-
-      const newId = newIdentifier(
-        this.address,
-        this.publicHex,
-        this.privateHex,
-        this.derivationPath,
-      );
-
-      const accountsDB = await accountsDBPromise;
-      if (this.shouldErase) {
-        const platformService = PlatformServiceFactory.getInstance();
-        await platformService.dbExec("DELETE FROM accounts");
-        if (USE_DEXIE_DB) {
-          await accountsDB.accounts.clear();
-        }
-      }
-      await saveNewIdentity(newId, mne, this.derivationPath);
       this.$router.push({ name: "account" });
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
     } catch (err: any) {
-      logger.error("Error saving mnemonic & updating settings:", err);
+      logger.error("Error importing from mnemonic:", err);
       if (err == "Error: invalid mnemonic") {
         this.$notify(
           {