docs: document Temp cleanup in CHANGELOG and ARCHITECTURE

docs/CHANGELOG.md

@@ -37,6 +37,24 @@ This changelog follows [Keep a Changelog](https://keepachangelog.com/) principle
 
 ---
 
+## [1.3.1] - 2026-02-22
+
+### Added
+
+- **Temp file cleanup after every download** (`src/core/providers/aniworld_provider.py`,
+  `src/core/providers/enhanced_provider.py`): Module-level helper
+  `_cleanup_temp_file()` removes the working temp file and any yt-dlp `.part`
+  fragments after each download attempt — on success, on failure, and on
+  exceptions (including `BrokenPipeError` and cancellation). Ensures that no
+  partial files accumulate in `./Temp/` across multiple runs.
+- **Temp folder purge on server start** (`src/server/fastapi_app.py`): The
+  FastAPI lifespan startup now iterates `./Temp/` and deletes every file and
+  sub-directory before the rest of the initialisation sequence runs. If the
+  folder does not exist it is created. Errors are caught and logged as warnings
+  so that they never abort startup.
+
+---
+
 ## [1.3.0] - 2026-02-22
 
 ### Added