Ktb2110 203 additional request fields

[KTB2110]

Summary

This PR implements the additional_request_details Lambda function for the Request Details tab. The frontend passes a request_id and the Lambda queries req_add_info in Virginia RDS and returns all additional fields for that request, grouped and structured by field type.

What was built

New file: data-analytics/lambda_functions/additional_request_details.py

Modelled after the existing kpi_api_analytics.py structure with:

• AWS SSM Parameter Store for DB credentials (no hardcoded values)
• RealDictCursor for named column access
• build_response() helper for consistent HTTP response format
• finally block to guarantee DB connection cleanup

Field value mapping logic

The core of this Lambda is a loop that groups rows from req_add_info by field_id and maps them differently based on the item_id / field_value combination:

item_id	field_value	Output
not null	null	"field_id": ["item_id1", "item_id2"]
not null	not null (non-datetime)	"field_id": {"item_id1": "val1", "item_id2": "val2"}
null	not null (non-datetime)	"field_id": "field_value"
not null	not null (datetime)	"field_id": {"item_id_date": "...", "item_id_time": "..."}
null	not null (datetime)	"field_id": {"field_id_date": "...", "field_id_time": "..."}

Date & time bifurcation

Date fields are detected dynamically using regex ^\d{4}-\d{2}-\d{2}T on field_value — no field IDs are hardcoded. When matched, the value is split on T into _date and _time keys. If item_id is present, it is used as the key prefix; if null, field_id is used as the prefix.

Error handling

Scenario	Status Code	Error Code
DB connection failure	500	DE 1000
Query execution failure	500	DE 1001
Missing request_id in payload	400	DE 1002
request_id not found in DB	200	empty additionalFields: {}

Error codes avoid leaking internal DB details to the browser.

Testing

Tested locally against req_add_info.csv loaded into saayam_local PostgreSQL. Verified all field type combinations including:

• Multi-select checkboxes (multiple item_ids under same field_id)
• Textbox fields (null item_id, direct field_value mapping)
• Date&time fields with item_id (6.1.B — PREFERRED_MOVE_OUT_DATE)
• Date&time fields without item_id (3.7.B)
• Mixed field types in the same request

Closes #203