US-5.10implemented Select period granularity (weekly / monthly / yearly)
As a user who wants to view my finances at different time scales I want choose between weekly, monthly, and yearly granularity, and have the period dropdown update accordingly so that I can view a single week, a single month, or an entire year of data.
Acceptance Criteria
- Three granularity buttons (Weekly, Monthly, Yearly) appear in the toolbar.
- Clicking a granularity button updates the period dropdown options to show weeks, months, or years respectively.
- "All Time" is always available regardless of granularity.
- Weekly periods show ISO week boundaries (Monday to Sunday).
- Yearly periods use a whole-year date range (`YYYY/1/1 to YYYY+1/1/1`).
No DAG diagram: Filtering/presentation feature on the visualisation layer; the underlying data path is the same as US-5.4.
Demo video coming soon