…-7.78.0 (#30391)

Revert the MMKV major bump that landed in #29195 (RN 0.81.5 upgrade).
The v3 -> v4 jump was not required by RN 0.81 / React 19 / Expo SDK 54
and shipped a latent crash in migration 106 (PPOM cleanup) because v4
makes `MMKV` a type-only export while migration 106 was still calling
`new MMKV(...)` against `require('react-native-mmkv').MMKV`.

CHANGELOG entry: null

Changes:

- package.json: `react-native-mmkv` ^4.1.2 -> ^3.2.0 (resolves to 3.3.3)
`react-native-nitro-modules` left pinned at 0.35.5 since
`react-native-vision-camera` and other packages still need the new Nitro
version.
- app/store/storage-wrapper.ts: `createMMKV()` -> `new MMKV()`,
`.remove(key)` -> `.delete(key)`, drop the `as MMKV` cast,
`EventEmitter2` named import restored.
- app/store/migrations/049.ts: factory -> constructor.
- app/store/migrations/106.ts: drop the `require` + `// eslint-disable`
workaround, use a plain `import { MMKV }`. Fixes the silent migration
failure on devices that had PPOM storage.
- app/store/migrations/136.ts: factory -> constructor, `.remove()` ->
`.delete()` (this migration was added in #29542 after the bump landed,
so it needed forward-translation to v3 rather than a true revert).
- app/store/migrations/106.test.ts, 136.test.ts: revert mock factory
exports from `createMMKV` to `MMKV`.
- app/util/notifications/settings/storage/index.ts: all three callsites
swapped from `createMMKV(...)` to `new MMKV(...)`.
- app/util/test/testSetup.js, testSetupView.js: drop `createMMKV` from
the module-level mock factory (v3 has no such export, so leaving it in
would mask real production bugs in tests).
- ios/Podfile.lock: regenerated. NitroMmkv pod + MMKVCore artifact
removed; react-native-mmkv v3 pod added.

Verified post-revert: no `createMMKV` references left in the codebase,
no `import type { MMKV }` left, no v4-style `.remove(key)` on MMKV
instances, lints clean across all touched files. `notificationStorage`
test still uses `import { MMKV }` for a type annotation, which works
since v3 exports `MMKV` as a class (value + type).

TODO before merge: run the unit-test suite and an iOS/Android smoke
build, plus the in-place upgrade canary scenario from #29195 to confirm
v3 binaries can still read MMKV files that were written by v4 in any
prior dev/internal build (production users are still on v3).

<!--
Please submit this PR as a draft initially.

Do not mark it as "Ready for review" until this PR meets the canonical
Definition of Ready For Review in `docs/readme/ready-for-review.md`.

In short: the template must be materially complete (not just section
titles
present), all status checks must be currently passing, and the only
expected
follow-up commits must be reviewer-driven.
-->

## **Description**

<!--
Write a short description of the changes included in this pull request,
also include relevant motivation and context. Have in mind the following
questions:
1. What is the reason for the change?
2. What is the improvement/solution?
-->

## **Changelog**

<!--
If this PR is not End-User-Facing and should not show up in the
CHANGELOG, you can choose to either:
1. Write `CHANGELOG entry: null`
2. Label with `no-changelog`

If this PR is End-User-Facing, please write a short User-Facing
description in the past tense like:
`CHANGELOG entry: Added a new tab for users to see their NFTs`
`CHANGELOG entry: Fixed a bug that was causing some NFTs to flicker`

(This helps the Release Engineer do their job more quickly and
accurately)
-->

CHANGELOG entry:

## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

<!-- [screenshots/recordings] -->

### **After**

<!-- [screenshots/recordings] -->

## **Pre-merge author checklist**

<!--
Every checklist item must be consciously assessed before marking this PR
as
"Ready for review". A checked box means you deliberately considered that
responsibility, not that you literally performed every action listed.

Unchecked boxes are ambiguous: they are not an implicit "N/A" and they
are not
a silent "skip". See `docs/readme/ready-for-review.md` for the full
checklist
semantics.
-->

- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

#### Performance checks (if applicable)

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

<!--
Reviewer checklist items follow the same semantics as the author
checklist: an
unchecked box is ambiguous, a checked box means the reviewer consciously
assessed that responsibility. See `docs/readme/ready-for-review.md`.
-->

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Reverts a major storage dependency version and updates MMKV
instantiation/deletion APIs across migrations and wrappers, which can
affect persistence and data cleanup behavior on upgrade. Risk is
mitigated by targeted code changes and updated Jest mocks/tests, but
should be validated with mobile smoke tests and migration paths.
> 
> **Overview**
> Reverts `react-native-mmkv` from v4 to v3 (updates `package.json`,
`yarn.lock`, and iOS pods) and removes the Nitro-related MMKV pods from
`Podfile.lock`.
> 
> Updates all touched call sites to match the v3 API: replaces
`createMMKV(...)` with `new MMKV(...)`, switches key deletion from
`.remove(...)` to `.delete(...)`, and simplifies migration `106` to use
a standard `import { MMKV }` (eliminating the prior `require`
workaround).
> 
> Adjusts Jest mocks and migration tests (`106`, `136`) to mock the
`MMKV` constructor-only export expected in v3 and to assert
`.delete(...)` behavior.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
042b30e. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Cursor <cursoragent@cursor.com>