Add a "Note" field to expenses

[gittiedank]

When logging expenses (shopping, groceries, food & drinks, etc.), there's no way to attach context to an entry beyond the amount and category. Details like what was bought, why, or a reminder for later get lost.

Add an optional free-text "Note" field to each expense entry, scoped to individual expenses.

It would be useful for things like:

• Specifying what a "Groceries" entry actually covered
• Noting who/what it was for, or a reimbursement reminder
• Flagging a receipt discrepancy or split detail

Currently stuffing extra context into the expense title, which clutters the budget view and defeats the category grouping.

[mauriceboe]

Coming in 4.0.0!