fix(import): ensure contact import works for both Dexie and absurd-sql backends

- Refactor importContacts to handle both Dexie and absurd-sql (SQLite) storage
- Add ContactDbRecord interface with all string fields strictly typed (never null)
- Add helper functions to coerce null/undefined to empty string for all string fields
- Guarantee contactMethods is always stored as a JSON string (never null)
- Add runtime validation for required fields (e.g., did)
- Ensure imported/updated contacts are type-safe and compatible with both backends
- Improve code documentation and maintainability

Security:
- No sensitive data exposed
- All fields validated and sanitized before database write
- Consistent data structure across storage backends

Testing:
- Import tested with both Dexie and absurd-sql backends
- Null/undefined fields correctly handled and coerced
- No linter/type errors remain

src/views/ContactImportView.vue

@@ -223,6 +223,75 @@ import { getContactJwtFromJwtUrl } from "../libs/crypto";
 import { decodeEndorserJwt } from "../libs/crypto/vc";
 import { PlatformServiceFactory } from "@/services/PlatformServiceFactory";
 
+/**
+ * Interface for contact data as stored in the database
+ * Differs from Contact interface in that contactMethods is stored as a JSON string
+ */
+interface ContactDbRecord {
+  did: string;
+  contactMethods: string;
+  name: string;
+  notes: string;
+  profileImageUrl: string;
+  publicKeyBase64: string;
+  nextPubKeyHashB64: string;
+  seesMe: boolean;
+  registered: boolean;
+}
+
+/**
+ * Ensures a value is a string, never null or undefined
+ */
+function safeString(val: unknown): string {
+  return typeof val === 'string' ? val : (val == null ? '' : String(val));
+}
+
+/**
+ * Converts a Contact object to a ContactDbRecord for database storage
+ * @param contact The contact object to convert
+ * @returns A ContactDbRecord with contactMethods as a JSON string
+ * @throws Error if contact.did is missing or invalid
+ */
+function contactToDbRecord(contact: Contact): ContactDbRecord {
+  if (!contact.did) {
+    throw new Error("Contact must have a DID");
+  }
+
+  // Convert contactMethods array to JSON string, defaulting to empty array
+  const contactMethodsStr = (contact.contactMethods != null
+    ? JSON.stringify(contact.contactMethods)
+    : "[]");
+
+  return {
+    did: safeString(contact.did),  // Required field, must be present
+    contactMethods: contactMethodsStr,
+    name: safeString(contact.name),
+    notes: safeString(contact.notes),
+    profileImageUrl: safeString(contact.profileImageUrl),
+    publicKeyBase64: safeString(contact.publicKeyBase64),
+    nextPubKeyHashB64: safeString(contact.nextPubKeyHashB64),
+    seesMe: contact.seesMe ?? false,
+    registered: contact.registered ?? false
+  };
+}
+
+/**
+ * Converts a ContactDbRecord back to a Contact object
+ * @param record The database record to convert
+ * @returns A Contact object with parsed contactMethods array
+ */
+function dbRecordToContact(record: ContactDbRecord): Contact {
+  return {
+    ...record,
+    name: safeString(record.name),
+    notes: safeString(record.notes),
+    profileImageUrl: safeString(record.profileImageUrl),
+    publicKeyBase64: safeString(record.publicKeyBase64),
+    nextPubKeyHashB64: safeString(record.nextPubKeyHashB64),
+    contactMethods: JSON.parse(record.contactMethods || "[]")
+  };
+}
+
 /**
  * Contact Import View Component
  * @author Matthew Raymer
@@ -533,25 +602,36 @@ export default class ContactImportView extends Vue {
       if (this.contactsSelected[i]) {
         const contact = this.contactsImporting[i];
         const existingContact = this.contactsExisting[contact.did];
+        const platformService = PlatformServiceFactory.getInstance();
+
+        // Convert contact to database record format
+        const contactToStore = contactToDbRecord(contact);
+
         if (existingContact) {
-          const platformService = PlatformServiceFactory.getInstance();
-          // @ts-expect-error because we're just using the value to store to the DB
-          contact.contactMethods = JSON.stringify(contact.contactMethods);
+          // Update existing contact
           const { sql, params } = databaseUtil.generateUpdateStatement(
-            contact as unknown as Record<string, unknown>,
+            contactToStore as unknown as Record<string, unknown>,
             "contacts",
             "did = ?",
             [contact.did],
           );
           await platformService.dbExec(sql, params);
           if (USE_DEXIE_DB) {
-            await db.contacts.update(contact.did, contact);
+            // For Dexie, we need to parse the contactMethods back to an array
+            await db.contacts.update(contact.did, dbRecordToContact(contactToStore));
           }
           updatedCount++;
         } else {
-          // without explicit clone on the Proxy, we get: DataCloneError: Failed to execute 'add' on 'IDBObjectStore': #<Object> could not be cloned.
-          // DataError: Failed to execute 'add' on 'IDBObjectStore': Evaluating the object store's key path yielded a value that is not a valid key.
-          await db.contacts.add(R.clone(contact));
+          // Add new contact
+          const { sql, params } = databaseUtil.generateInsertStatement(
+            contactToStore as unknown as Record<string, unknown>,
+            "contacts",
+          );
+          await platformService.dbExec(sql, params);
+          if (USE_DEXIE_DB) {
+            // For Dexie, we need to parse the contactMethods back to an array
+            await db.contacts.add(dbRecordToContact(contactToStore));
+          }
           importedCount++;
         }
       }