feat(notes): fill in the name of a new note from a template

[dionmunk]

Every new note needed a name typed in, even a quick one meant to be renamed later (#61).

Changes

• New setting notes.newNoteName: a name template using VS Code's snippet date and time variables, for example ${CURRENT_YEAR}-${CURRENT_MONTH}-${CURRENT_DATE} ${CURRENT_HOUR}-${CURRENT_MINUTE} for 2026-10-07 14-35.
• New Note (title bar buttons, Alt+N, the command palette) fills the name box with it, selected, so Enter creates the note with that name and typing replaces it.
• Empty by default, so nothing changes until someone sets it.
• All the CURRENT_* variables from the VS Code docs are supported, as ${NAME} or $NAME. Month and day names follow VS Code's display language. Unknown variables and other text are kept as typed, as in snippets.
• The setting's description recommends - between time parts: : isn't allowed in file names on Windows, and New Note already removes it.

A daily-note command (open today's note, creating it if needed), also mentioned in #61, was left out as too specialized for Notes.

Testing

• npm test: 47 passing, 6 new tests for the template (each date and time variable with padding, short year and milliseconds, month and day names, $NAME with the longest name winning, unix time, unknown variables kept).

• End to end in VS Code 1.140 on macOS, at about 10:25 local time:

  Case	Name box	Note created
  no template	empty	nothing on an empty Enter, as before
  date template, Enter	2026-10-07 10-25, all selected	2026-10-07 10-25.md with # 2026-10-07 10-25
  date template, typed a name	2026-10-07 10-26, all selected	custom name.md
  ${CURRENT_HOUR}:${CURRENT_MINUTE} call	10:27 call	1027 call.md
  Alt+N	2026-10-07 10-27, all selected	2026-10-07 10-27.md

Closes #61.