feat(calendar): show notes on calendar with day dots and hover summary

[h4yfans]

What

Adds a Show notes on calendar setting (on by default) and surfaces notes across the calendar surfaces.

Setting + calendar chips

• New showNotesOnCalendar calendar setting (Settings → Calendar), default on.
• The range projection plots notes as all-day chips on the day each note was created — read-side only, no date is written to any note.
• The calendar range refetches when calendar settings change.

Day dots

• The Day Panel / journal-tab calendar shows a notes dot on days with notes, alongside the event and journal-activity dots.
• Journal-activity and projection dots now render together instead of either/or.

Day-cell hover summary

• Hovering a date opens a 200 ms summary card: counts of notes / journal / tasks / events / reminders, each color-coded. Only kinds present that day are listed.

Implementation notes

• buildDaySummaries / buildDayDots roll up projection items per local day; journal is 0/1 from the heatmap level.
• Reuses the existing Radix HoverCard and the common:count.* ICU plural keys.
• calendar-handlers.ts added to the existing IPC-handlers max-lines eslint exemption (peer of notes-/settings-handlers, same Phase-2 split debt).

Tests

• projection: notes plotted by created date, journals excluded, gated by the setting.
• day-dots: event + note yield two distinct dots.
• day-summary: counts, reminders fold, journal 0/1.
• date-picker: activity + note dots coexist; hover wrapper does not swallow day clicks.
• Green: renderer + main calendar/settings suites, typecheck, lint, i18n, docs build.

[github-actions]

React Doctor found no issues. 🎉

_{Reviewed by React Doctor for commit 0833b88.}