fix(datetime): standardize Vietnam timezone and business dates (!25) · Merge Requests · ThinhNC / finwise-miniapp-be

fix(datetime): standardize Vietnam timezone and business dates

Summary

Standardize date and time handling across the backend using Asia/Ho_Chi_Minh as the business timezone.

Key Changes

Introduced centralized business-time utilities using the IANA timezone.
Changed Transaction date, Budget startDate/endDate, and Saving Goal targetDate to date-only values.
Changed absolute timestamp columns to PostgreSQL TIMESTAMPTZ(3).
Made Budget endDate inclusive.
Removed client-provided timezone offsets from report APIs.
Resolved report boundaries using the Vietnam business timezone.
Updated monthly and yearly reminder recurrence to preserve Vietnam wall-clock time.
Made token expiration independent of the server timezone.
Updated notification, AI context, seed data, and Swagger contracts.

API Changes

Business dates now use YYYY-MM-DD.
Report requests no longer accept timezoneOffsetMinutes.
Report responses include timeZone: "Asia/Ho_Chi_Minh".
Absolute datetimes continue using offset-aware ISO 8601 timestamps.

Database

Applied migration:

20260816090000_standardize_business_time

The migration:

Converts business calendar fields to PostgreSQL DATE.
Converts absolute timestamps to TIMESTAMPTZ(3).
Preserves existing dates according to Asia/Ho_Chi_Minh.

Seed data was successfully regenerated.

## Summary

Standardize date and time handling across the backend using `Asia/Ho_Chi_Minh` as the business timezone.

## Key Changes

- Introduced centralized business-time utilities using the IANA timezone.
- Changed Transaction `date`, Budget `startDate/endDate`, and Saving Goal `targetDate` to date-only values.
- Changed absolute timestamp columns to PostgreSQL `TIMESTAMPTZ(3)`.
- Made Budget `endDate` inclusive.
- Removed client-provided timezone offsets from report APIs.
- Resolved report boundaries using the Vietnam business timezone.
- Updated monthly and yearly reminder recurrence to preserve Vietnam wall-clock time.
- Made token expiration independent of the server timezone.
- Updated notification, AI context, seed data, and Swagger contracts.

## API Changes

- Business dates now use `YYYY-MM-DD`.
- Report requests no longer accept `timezoneOffsetMinutes`.
- Report responses include `timeZone: "Asia/Ho_Chi_Minh"`.
- Absolute datetimes continue using offset-aware ISO 8601 timestamps.

## Database

Applied migration:

`20260816090000_standardize_business_time`

The migration:

- Converts business calendar fields to PostgreSQL `DATE`.
- Converts absolute timestamps to `TIMESTAMPTZ(3)`.
- Preserves existing dates according to `Asia/Ho_Chi_Minh`.

Seed data was successfully regenerated.