fix: update start index for proposed account name for pk/hardware imports (#6677)

## Explanation

Currently, PK/Hardware imports were being started at `Account 2` as
opposed to `Account 1`. When we apply group metadata we already have
that group in state, the logic in `#applyGroupMetadata` doesn't account
for the fact that the group we're applying metadata shouldn't be counted
for in the following line:
https://github.com/MetaMask/core/blob/main/packages/account-tree-controller/src/AccountTreeController.ts#L461.
Due to the way we apply group metadata (after we've added the groups
into state), we need to take the min between `proposedNameIndex` and
`highestAccountNameIndex` NOT the max. This change in logic accounts for
group metadata being applied in the scenario when the controller is
being rehydrated through `init` and when a new pk/hardware account is
added in an active session (and handled through `accountAdded`).

## Before


https://github.com/user-attachments/assets/8ab1b3c6-574f-45bc-bf3a-3a3de7b45836

## After 


https://github.com/user-attachments/assets/66e53362-e587-45d3-b7ae-43e09da17a09

## Checklist

- [x] I've updated the test suite for new or updated code as appropriate
- [x] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [x] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs),
highlighting breaking changes as necessary
- [x] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

Author: hmalik88

packages/account-tree-controller/CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix group naming for PK/Hardware accounts ([#6677](https://github.com/MetaMask/core/pull/6677))
+  - Previously, the first PK/Hardware account would start as `Account 2` as opposed to `Account 1` and thus subsequent group names were off as well.
+
 ## [1.0.0]
 
 ### Changed

packages/account-tree-controller/src/AccountTreeController.test.ts

@@ -587,7 +587,7 @@ describe('AccountTreeController', () => {
                   type: AccountGroupType.SingleAccount,
                   accounts: [MOCK_SNAP_ACCOUNT_2.id],
                   metadata: {
-                    name: 'Account 2', // Updated: per-wallet numbering (different wallet)
+                    name: 'Account 1', // Updated: per-wallet numbering (different wallet)
                     pinned: false,
                     hidden: false,
                   },
@@ -610,7 +610,7 @@ describe('AccountTreeController', () => {
                   type: AccountGroupType.SingleAccount,
                   accounts: [MOCK_HARDWARE_ACCOUNT_1.id],
                   metadata: {
-                    name: 'Account 2', // Updated: per-wallet numbering (different wallet)
+                    name: 'Account 1', // Updated: per-wallet numbering (different wallet)
                     pinned: false,
                     hidden: false,
                   },
@@ -652,13 +652,13 @@ describe('AccountTreeController', () => {
           },
           [expectedKeyringWalletIdGroup]: {
             name: {
-              value: 'Account 2', // Updated: per-wallet numbering (different wallet)
+              value: 'Account 1', // Updated: per-wallet numbering (different wallet)
               lastUpdatedAt: expect.any(Number),
             },
           },
           [expectedSnapWalletIdGroup]: {
             name: {
-              value: 'Account 2', // Updated: per-wallet numbering (different wallet)
+              value: 'Account 1', // Updated: per-wallet numbering (different wallet)
               lastUpdatedAt: expect.any(Number),
             },
           },
@@ -2430,8 +2430,8 @@ describe('AccountTreeController', () => {
 
       // Groups should use consistent default naming regardless of import time
       // Updated expectations based on per-wallet sequential naming logic
-      expect(group1?.metadata.name).toBe('Account 3'); // Updated: reflects actual naming logic
-      expect(group2?.metadata.name).toBe('Account 2'); // Updated: reflects actual naming logic
+      expect(group1?.metadata.name).toBe('Account 2'); // Updated: reflects actual naming logic
+      expect(group2?.metadata.name).toBe('Account 1'); // Updated: reflects actual naming logic
     });
 
     it('uses fallback naming when rule-based naming returns empty string', () => {
@@ -2902,9 +2902,9 @@ describe('AccountTreeController', () => {
       // Critical assertion: should have 2 unique names (no duplicates)
       expect(uniqueNames.size).toBe(2);
 
-      // Due to optimization, names start at wallet.length, so we get "Account 3" and "Account 4"
-      expect(allNames).toContain('Account 3');
-      expect(allNames).toContain('Account 4');
+      // Due to optimization, names start at wallet.length, so we get "Account 1" and "Account 2"
+      expect(allNames).toContain('Account 1');
+      expect(allNames).toContain('Account 2');
 
       // Verify they're actually different
       expect(group1.metadata.name).not.toBe(group2.metadata.name);

packages/account-tree-controller/src/AccountTreeController.ts

@@ -458,11 +458,11 @@ export class AccountTreeController extends BaseController<
       } else {
         // For other wallet types, start with the number of existing groups
         // This gives us the next logical sequential number
-        proposedNameIndex = Object.keys(wallet.groups).length;
+        proposedNameIndex = Object.keys(wallet.groups).length - 1;
       }
 
       // Use the higher of the two: highest parsed index or computed index
-      proposedNameIndex = Math.max(highestAccountNameIndex, proposedNameIndex);
+      proposedNameIndex = Math.min(highestAccountNameIndex, proposedNameIndex);
 
       // Find a unique name by checking for conflicts and incrementing if needed
       let nameExists: boolean;