fix: exclude account_id and virtual fields from archive_content DB writes

- Adds fields_to_exclude_from_db to Archive_Content_Base to prevent SQL errors on non-existent columns.
- Updates documentation for V3 Create/Update patterns and the x-ae-ignore-extra-fields header.
- Propagates account_id_random to hosted file and media processing methods.

app/models/archive_content_models.py

@@ -1,6 +1,6 @@
 import datetime, pytz
 
-from typing import Dict, List, Optional, Set, Union
+from typing import Dict, List, Optional, Set, Union, ClassVar
 from pydantic import BaseModel, EmailStr, Field, Json, PrivateAttr, ValidationError, validator
 
 from app.db_sql import redis_lookup_id_random
@@ -92,6 +92,13 @@ class Archive_Content_Base(BaseModel):
     hosted_file_content_type: Optional[str]
     hosted_file_size: Optional[str]
 
+    # 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', 'account_id_random', 'archive_id_random', 'hosted_file_id_random',
+        'hosted_file_path', 'api_hosted_file_path_download', 'api_hosted_file_path_stream',
+        'hosted_file_hash_sha256', 'hosted_file_content_type', 'hosted_file_size'
+    ]
+
     _processed_at: datetime.datetime = PrivateAttr(default_factory=datetime.datetime.now)
 
     @validator('id', always=True)