docs: Update API, CHANGELOG, and ARCHITECTURE for Enhanced Anime Add Flow

docs/ARCHITECTURE.md

@@ -90,6 +90,10 @@ src/server/
 |   +-- connection.py       # Database connection
 |   +-- models.py           # ORM models
 |   +-- service.py          # Database service
++-- utils/                  # Utility modules
+|   +-- filesystem.py       # Folder sanitization, path safety
+|   +-- validators.py       # Input validation utilities
+|   +-- dependencies.py     # FastAPI dependency injection
 +-- web/                    # Static files and templates
     +-- static/             # CSS, JS, images
     +-- templates/          # Jinja2 templates
@@ -104,10 +108,10 @@ Domain logic for anime series management.
 ```
 src/core/
 +-- SeriesApp.py            # Main application facade
-+-- SerieScanner.py         # Directory scanning
++-- SerieScanner.py         # Directory scanning, targeted single-series scan
 +-- entities/               # Domain entities
-|   +-- series.py           # Serie class
-|   +-- SerieList.py        # SerieList collection
+|   +-- series.py           # Serie class with sanitized_folder property
+|   +-- SerieList.py        # SerieList collection with sanitized folder support
 +-- providers/              # External provider adapters
 |   +-- base_provider.py    # Loader interface
 |   +-- provider_factory.py # Provider registry
@@ -117,6 +121,15 @@ src/core/
     +-- Exceptions.py       # Custom exceptions
 ```
 
+**Key Components:**
+
+| Component         | Purpose                                                                 |
+| ----------------- | ----------------------------------------------------------------------- |
+| `SeriesApp`       | Main application facade for anime operations                            |
+| `SerieScanner`    | Scans directories for anime; `scan_single_series()` for targeted scans  |
+| `Serie`           | Domain entity with `sanitized_folder` property for filesystem-safe names |
+| `SerieList`       | Collection management with automatic folder creation using sanitized names |
+
 Source: [src/core/](../src/core/)
 
 ### 2.4 Infrastructure Layer (`src/infrastructure/`)