[enhancement] set calendar color inside of the note

[throwaway-nolsh]

currently, it seems to me that the colors of calendars are handled internally on a per-file basis, so changing the name of a calendar file will remove all previously defined colors

i think it'd be nice that, in the spirit of doing everything in markdown, you could specify the color of a calendar inside the heading directly.

something like:

# Calendar

## University {color:bbaa11}
- [ ] study for test {date here}
- [ ] computer science test

...or on the first line below the heading
## Birthdays
{color:ccff77}
- [ ] Joe 🔁 every year 📅 2026-01-05
- [ ] John 🔁 every year 📅 2026-05-11

im not sure of a fitting syntax, this is moreso for the idea