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/libs/util.ts

@@ -45,6 +45,7 @@ import { PlatformServiceFactory } from "@/services/PlatformServiceFactory";
 import { sha256 } from "ethereum-cryptography/sha256";
 import { IIdentifier } from "@veramo/core";
 import { insertDidSpecificSettings, parseJsonField } from "../db/databaseUtil";
+import { DEFAULT_ROOT_DERIVATION_PATH } from "./crypto";
 
 export interface GiverReceiverInputInfo {
   did?: string;
@@ -998,3 +999,38 @@ export const contactsToExportJson = (contacts: Contact[]): DatabaseExport => {
     },
   };
 };
+
+/**
+ * Imports an account from a mnemonic phrase
+ * @param mnemonic - The seed phrase to import from
+ * @param derivationPath - The derivation path to use (defaults to DEFAULT_ROOT_DERIVATION_PATH)
+ * @param shouldErase - Whether to erase existing accounts before importing
+ * @returns Promise that resolves when import is complete
+ * @throws Error if mnemonic is invalid or import fails
+ */
+export async function importFromMnemonic(
+  mnemonic: string,
+  derivationPath: string = DEFAULT_ROOT_DERIVATION_PATH,
+  shouldErase: boolean = false,
+): Promise<void> {
+  const mne: string = mnemonic.trim().toLowerCase();
+
+  // Derive address and keys from mnemonic
+  const [address, privateHex, publicHex] = deriveAddress(mne, derivationPath);
+
+  // Create new identifier
+  const newId = newIdentifier(address, publicHex, privateHex, derivationPath);
+
+  // Handle database operations
+  const accountsDB = await accountsDBPromise;
+  if (shouldErase) {
+    const platformService = PlatformServiceFactory.getInstance();
+    await platformService.dbExec("DELETE FROM accounts");
+    if (USE_DEXIE_DB) {
+      await accountsDB.accounts.clear();
+    }
+  }
+
+  // Save the new identity
+  await saveNewIdentity(newId, mne, derivationPath);
+}