feat(docs): add developer-friendly release notes for v4.0.0

Add comprehensive release notes for alpha.0 and beta.0 releases:
- RELEASE_NOTES_v4.0.0-alpha.0.md - Infrastructure changes
- RELEASE_NOTES_v4.0.0-beta.0.md - Features and migration guide

Follows best practices from TypeScript, Next.js, and Vitest:
- Concise, scannable format
- Before/after code examples
- Real-world context
- Clear migration steps
- Technical tone without sales pitch
- PR references
- Direct links to resources

Also updates failFast() TypeScript type to only accept { enabled: false }
since fail-fast is ON by default in v4 and the method only exists to disable it.

Author: omermorad

RELEASE_NOTES_v4.0.0-alpha.0.md

@@ -0,0 +1,172 @@
+# v4.0.0-alpha.0 (2025-10-27)
+
+Infrastructure modernization release. All changes are breaking and relate to runtime environment and module system.
+
+## Summary
+
+- Node.js 20+ required (dropped 16.x and 18.x)
+- All packages migrated to dual CJS/ESM builds
+- Manual type augmentation configuration required
+- InversifyJS v7 upgrade
+- Migrated from Yarn to pnpm
+
+---
+
+## Breaking Changes
+
+### Node.js Version
+
+Minimum version increased to Node.js 20.x. (#803)
+
+**Before**: Node.js 16.x, 18.x supported
+**After**: Node.js 20.x, 22.x, 24.x required
+
+```bash
+# Migration
+node --version  # Must be >= 20.0.0
+nvm install 20
+nvm use 20
+```
+
+---
+
+### Module System
+
+All packages now output dual CJS/ESM builds to `dist/cjs/` and `dist/esm/`.
+
+**Before**:
+```
+node_modules/@suites/unit/
+  dist/
+    index.js
+    services/
+```
+
+**After**:
+```
+node_modules/@suites/unit/
+  dist/
+    cjs/
+      index.js
+      services/
+    esm/
+      index.js
+      services/
+```
+
+**Impact**: Direct file imports must update paths (normal imports unchanged).
+
+```typescript
+// Normal imports work unchanged
+import { TestBed } from '@suites/unit';  // ✓ Still works
+
+// Direct imports need update
+import { something } from '@suites/unit/dist/services/builder';  // Old
+import { something } from '@suites/unit/dist/cjs/services/builder';  // New
+```
+
+**Affected packages**: All 10 packages
+**Commits**: Multiple commits, one per package
+
+---
+
+### Type Augmentation
+
+Postinstall scripts removed. Manual configuration required.
+
+**Before**: Types automatically injected via postinstall scripts
+**After**: Create `global.d.ts` manually
+
+**Migration**:
+
+1. Create `global.d.ts` in project root:
+```typescript
+/// <reference types="@suites/doubles.jest/unit" />
+/// <reference types="@suites/di.nestjs/types" />
+```
+
+2. Add to `tsconfig.json`:
+```json
+{
+  "include": ["src", "global.d.ts"]
+}
+```
+
+**Affected packages**:
+- `@suites/doubles.jest`
+- `@suites/doubles.vitest`
+- `@suites/doubles.sinon`
+- `@suites/di.inversify`
+- `@suites/di.nestjs`
+
+**Why**: Postinstall scripts caused CI/CD issues and violated npm best practices.
+
+---
+
+### InversifyJS v7
+
+`@suites/di.inversify` now requires InversifyJS v7.x. (#884)
+
+```bash
+npm install inversify@^7.0.0 reflect-metadata@^0.2.2
+```
+
+**What changed**: Uses InversifyJS v7 metadata API
+
+---
+
+## Improvements
+
+### Package Manager
+- Migrated from Yarn to pnpm 10.14.0 (#799)
+- Faster installs, better workspace support
+
+### Dependencies
+- Removed lodash.isequal, using Node.js `util.isDeepStrictEqual()`
+- Lighter dependency footprint
+
+### License
+- Changed from MIT to Apache-2.0
+
+---
+
+## Bug Fixes
+
+- Fixed missing `@suites/types.doubles` dependency in core (#806)
+- Upgraded ts-mocha for Node 22/24 compatibility
+
+---
+
+## Documentation
+
+Added comprehensive JSDoc to:
+- `@suites/unit` - TestBed API
+- `@suites/core.unit` - Core implementation
+- `@suites/doubles.jest` - Jest adapter
+- `@suites/doubles.vitest` - Vitest adapter
+- `@suites/doubles.sinon` - Sinon adapter
+- All type packages
+
+---
+
+## Migration Checklist
+
+- [ ] Upgrade Node.js to 20+
+- [ ] Install alpha: `npm install @suites/[email protected]`
+- [ ] Create `global.d.ts` with type references
+- [ ] Add `global.d.ts` to `tsconfig.json` include array
+- [ ] If using Inversify: `npm install inversify@^7.0.0`
+- [ ] Run tests
+- [ ] Update CI/CD Node.js version
+
+---
+
+## Installation
+
+```bash
+npm install @suites/[email protected]
+```
+
+---
+
+**Full Changelog**: https://github.com/suites-dev/suites/compare/v3.0.2...v4.0.0-alpha.0