[31b4]

Closes #185

Summary

Follow-up to #183: every date chart now uses calendar-aligned x-axis labels, and year labels among month labels are emphasized. Per-account trend charts also start on the period's first day and show correct balances for past periods.

Changes

• Calendar axis everywhere: InteractiveAreaChart always uses calendarTicks, so the per-account trends and portfolio history get them (the opt-in prop is removed). A new useCalendarAxis hook (common/calendar-axis.tsx) measures the chart width and gives Recharts time axes the same ticks with edge-aware anchors. It is used by the investment detail chart, manual valuations and the AI cash outlook (which keeps its local-midnight timestamps).
• Year emphasis: calendarTicks marks a year label among month labels as major. Those labels render in the foreground colour at semibold weight, and the area chart adds a faint dashed guide at each year start. Year-only axes stay unemphasized.
• Per-account trends: balances are rebuilt from the account's whole ledger, then clipped with clipBalancesToPeriod, as Cash Balance Trend does. Before, past months and years were walked back from today's balance without the later movements, so they were offset. 1M now fills daily from the 1st with the carried balance, and finished periods carry to their last day. Accounts still appear only when they have a transaction in the period.

Verification

• npm test -w client: 61 files, 572 tests passed. New tests cover major year ticks, area-chart year emphasis, the Recharts tick hook (UTC and local times, empty range) and per-account clipping for current and past months.
• npm run lint -w client -- --max-warnings=0: clean.
• VITE_API_AUTH_MODE=public VITE_API_DOMAIN=localhost:8787 npm run build: built.
• Manual check against a local API with two years of synthetic data:
  • Analytics All, desktop: Cash Balance Trend and the per-account chart both show 2025 Apr Jul Oct 2026 Apr Jul Oct, with the years bold.
  • Analytics All, mobile (375px): 2025 Jul 2026 Jul, no horizontal scroll.
  • 1Y: Jan … Oct. 1M: Oct 1, 4 … 28.
  • Previous month (September): the per-account chart matches Cash Balance Trend, running Sep 1–30 with the same closing balance.
  • Portfolio history (no holdings): calendar days.
• Not checked visually: the investment detail chart, manual valuations and the AI cash outlook, because the local data has no holdings, appraisals or forecast snapshot. Unit tests cover their shared hook.