Release/606.0.0 (#6800)

## Release @metamask/core-backend@1.0.0

This PR releases the initial version of the `@metamask/core-backend`
package.

### 📦 Package Overview

`@metamask/core-backend` provides core backend services for MetaMask,
serving as the data layer between Backend services (REST APIs, WebSocket
services) and Frontend applications (Extension, Mobile). This package
enables authenticated real-time data delivery with type-safe controller
integration.

### ✨ What's New in v1.0.0

This is the **initial release** of the package, introducing:

#### Core Services

- **BackendWebSocketService** - WebSocket client providing authenticated
real-time data delivery with:
- Connection management and automatic reconnection with exponential
backoff
  - Message routing and subscription management
  - Authentication integration with `AuthenticationController`
  - Type-safe messenger-based API for controller integration

- **AccountActivityService** - High-level service for monitoring account
activity with:
  - Real-time account activity monitoring via WebSocket subscriptions
- Balance update notifications for integration with
`TokenBalancesController`
  - Chain status change notifications for dynamic polling coordination
  - Account subscription management with automatic cleanup

#### Infrastructure

- **Type definitions** - Comprehensive TypeScript types for
transactions, balances, WebSocket messages, and service configurations
- **Logging infrastructure** - Structured logging with module-specific
loggers for debugging and monitoring

### 📄 Changelog

See
[CHANGELOG.md](https://github.com/MetaMask/core/blob/main/packages/core-backend/CHANGELOG.md)
for full details.

### 🔗 Related PR

- Initial implementation: #6722

### ✅ Release Checklist

- [x] Version bump is correct (1.0.0 for initial release)
- [x] Changelog entries are accurate and comprehensive
- [x] All changes are properly documented
- [x] Package is ready for publication
- [x] No additional changes from `main` need to be incorporated

### 📚 Documentation

- [Package
README](https://github.com/MetaMask/core/blob/main/packages/core-backend/README.md)
- [Architecture
documentation](https://github.com/MetaMask/core/blob/main/packages/core-backend/README.md#architecture--design)

---

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> Publishes initial @metamask/core-backend v1.0.0 with changelog updates
and bumps monorepo version to 606.0.0.
> 
> - **Releases**:
> - `@metamask/core-backend@1.0.0`: initial release; adds formal
changelog section and release links in
`packages/core-backend/CHANGELOG.md`.
> - **Versioning**:
>   - Monorepo `package.json` version bumped `605.0.0` -> `606.0.0`.
> - `packages/core-backend/package.json` version set `0.0.0` -> `1.0.0`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
0d6d6dd. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: Kriys94

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@metamask/core-monorepo",
-  "version": "605.0.0",
+  "version": "606.0.0",
   "private": true,
   "description": "Monorepo for packages shared between MetaMask clients",
   "repository": {

packages/core-backend/CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.0.0]
+
 ### Added
 
 - **Initial release of `@metamask/core-backend` package** - Core backend services for MetaMask serving as the data layer between Backend services and Frontend applications ([#6722](https://github.com/MetaMask/core/pull/6722))
@@ -23,4 +25,5 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Type definitions** - Comprehensive TypeScript types for transactions, balances, WebSocket messages, and service configurations
 - **Logging infrastructure** - Structured logging with module-specific loggers for debugging and monitoring
 
-[Unreleased]: https://github.com/MetaMask/core/
+[Unreleased]: https://github.com/MetaMask/core/compare/@metamask/core-backend@1.0.0...HEAD
+[1.0.0]: https://github.com/MetaMask/core/releases/tag/@metamask/core-backend@1.0.0

packages/core-backend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@metamask/core-backend",
-  "version": "0.0.0",
+  "version": "1.0.0",
   "description": "Core backend services for MetaMask",
   "keywords": [
     "MetaMask",