refactor: remove obsolete resource download and installer endpoints

- Deleted the `POST /resources/get/{dataFolder?}` and `GET /resources/get-installer` endpoints as part of the architectural shift towards simplified resource management.
- Removed associated methods and configurations, including `ResourcesService.GetEncryptedResource`, `ResourcesService.GetInstaller`, and related properties in `ResourcesConfig`.
- Cleaned up environment variables and configuration files to reflect the removal of installer-related settings.
- Eliminated the `GetResourceRequest` DTO and its validator, along with the `WrongResourceName` error code.
- Updated documentation to clarify the changes in resource handling and the retirement of per-user file encryption.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/02_document/common-helpers/01_helper_extensions.md

@@ -5,7 +5,8 @@ Shared utility extensions used across multiple components.
 ## Modules
 - `EnumExtensions` — enum description/attribute extraction (used by BusinessException)
 - `StringExtensions` — PascalCase → snake_case conversion (used by AzaionDbSchemaHolder)
-- `StreamExtensions` — Stream → string conversion (used by SecurityTest)
+<!-- StreamExtensions removed in cycle 2 (2026-05-14): only consumer was the deleted SecurityTest. -->
+
 - `QueryableExtensions` — conditional LINQ Where filter (used by UserService)
 
 ## Consumers