[AZ-189] [AZ-190] [AZ-191] [AZ-192] [AZ-193] [AZ-194] [AZ-195] Add e2e blackbox test suite

Made-with: Cursor

_docs/02_document/modules/services_cache.md

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+# Module: Azaion.Services.Cache
+
+## Purpose
+In-memory caching abstraction using LazyCache, providing get-or-add and invalidation operations.
+
+## Public Interface
+
+### ICache
+| Method | Signature | Description |
+|--------|-----------|-------------|
+| `GetFromCacheAsync<T>` | `Task<T> GetFromCacheAsync<T>(string key, Func<Task<T>> fetchFunc, TimeSpan? expiration = null)` | Returns cached value or fetches and caches it |
+| `Invalidate` | `void Invalidate(string key)` | Removes a key from the cache |
+
+### MemoryCache (implementation)
+Default expiration: 4 hours (`TimeSpan.FromHours(4)`).
+
+## Internal Logic
+Wraps `LazyCache.CachingService`. `GetFromCacheAsync` uses `GetOrAddAsync` with absolute expiration relative to now. `Invalidate` calls `Remove`.
+
+## Dependencies
+- LazyCache (`IAppCache`, `CachingService`)
+
+## Consumers
+- `UserService.GetByEmail` — caches user lookups by `User.GetCacheKey(email)`
+- `UserService.UpdateHardware`, `UserService.UpdateQueueOffsets`, `UserService.CheckHardwareHash` — invalidate cache after writes
+- Registered as `Scoped` in DI (`Program.cs`): `AddScoped<ICache, MemoryCache>`
+
+## Data Models
+None.
+
+## Configuration
+None — default 4-hour expiration is hardcoded.
+
+## External Integrations
+None.
+
+## Security
+None.
+
+## Tests
+`MemoryCache` is instantiated directly in `UserServiceTest`.