feat: Implement V3 ID Vision and fields_to_exclude_from_db across core models

This commit refactors numerous Pydantic models to align with the V3 ID Vision standard, ensuring that primary and foreign key fields are represented as clean string IDs in the API. It also introduces and populates the  ClassVar in each model to prevent view-only fields and linked objects from being inadvertently written to the database during PATCH/POST operations.

Specifically, this includes:
- Adding  to exclude view-derived or joined fields such as , , nested objects (e.g., , ), and convenience fields (e.g., ).
- Adjusting root validators to correctly map string IDs and strip internal integer IDs for API responses.
- Resolving a KeyError by adding  to .

These changes are crucial for maintaining data integrity and consistency with the V3 API architecture.

app/models/event_session_models.py

@@ -216,6 +216,7 @@ class Event_Session_Base(BaseModel):
 
     # Fields that are part of the model (for reading) but should not be saved to the DB table
     fields_to_exclude_from_db: ClassVar[list] = [
+        'account_id',
         'file_count', 'internal_use_count', 'event_file_id_li_json', 'file_count_all',
         'event_name', 'event_start_datetime', 'event_end_datetime', 
         'event_location_name', 'event_track_name',