feat: Implement Event File Hosted Data Fix and API Guide Update

Address critical data visibility issues for Event Files and enhance frontend documentation.

This commit resolves the persistent problem where top-level hosted file convenience fields
(e.g., , , ) were
returning as  in V3 Event File API responses, even when .

Key changes include:
- Refactored  Pydantic model:
    - Removed redundant  definitions from top-level hosted file convenience fields,
      allowing direct mapping from SQL view columns.
    - Simplified  to focus solely on conditionally loading the nested
       object, as top-level fields are now populated directly by Pydantic
      from the  view.
    - Added comprehensive comments to clarify data flow, Pydantic's behavior, and the
      expected origin of these convenience fields from SQL views.
- Updated :
    - Introduced a new section detailing how to retrieve Event File data, including the
      use of  to get both top-level convenience fields and a nested
       object.
    - Clarified all ID references as random string IDs.
    - Renumbered the troubleshooting section.
- Copied updated guide to .
- Continued ID Vision compliance audit, ensuring consistent handling of random string IDs
  across various core and event models (Account, Address, Contact, DataStore, Event Badge Template).
- Consolidated ID Vision E2E tests and updated related documentation.
- Minor updates to  and
  to support Event File data retrieval with .

documentation/GUIDE__V3_FRONTEND_API.md

@@ -60,7 +60,26 @@ The primary way to retrieve data.
 
 ---
 
-## 4. Troubleshooting 403 Forbidden
+## 4. Event File Data Retrieval (Hosted Files)
+
+Event Files (`event_file`) often have associated Hosted Files (`hosted_file`) which contain binary data and metadata like SHA256 hashes, content types, and sizes. To retrieve this additional data:
+
+*   **Endpoint:** `GET /v3/crud/event_file/{event_file_id_random}`
+*   **Query Parameter:** Add `inc_hosted_file=true`
+    *   Example: `/v3/crud/event_file/<event_file_id_random>?inc_hosted_file=true`
+
+**Response Impact:**
+
+1.  **Top-Level Convenience Fields:** The response will include top-level fields for commonly needed hosted file data. These are populated directly from the SQL view via JOINs.
+    *   `hosted_file_hash_sha256` (string)
+    *   `hosted_file_subdirectory_path` (string)
+    *   `hosted_file_content_type` (string)
+    *   `hosted_file_size` (string - in bytes)
+2.  **Nested Hosted File Object:** A full `hosted_file` object will be nested under the `hosted_file` key. This object (`Hosted_File_Base` model) will contain all its standard fields, including `id` (random string ID), `hash_sha256`, `content_type`, `size`, etc.
+
+---
+
+## 5. Troubleshooting 403 Forbidden
 
 If you receive a 403 on a valid ID:
 1.  Verify `x-aether-api-key` is correct.