2026-07-18 — P1-4 modal migration: finance/* complete + new `<Drawer>` component

Branch: feat/p1-4-modals-finance Worktree: .worktrees/feat-p1-4-modals-finance

Why

Closes the remaining finance/* modals that the prior partial PR couldn't reach because they needed either a centered modal or a side drawer.

Right-side slide-in panel component. Symmetric to <Modal>:

open, onClose, title, icon, maxWidth, zIndex, footer, children — same shape as <Modal> props.
Body uses <DrawerHeader> (sticky top) and <DrawerFooter> (sticky bottom) slots.
Default maxWidth is max-w-2xl (vs Modal's max-w-xl).
Default zIndex is 110 (same as Modal).
Backdrop click-outside + Escape-to-close + scroll-lock behaviour matches Modal.

Delete group? (confirm) — red destructive dialog.
New student group / Edit X — name + description + type + colour form.
Add members to X — mode dropdown (all / by class / by IDs) with conditional UID input.

Invoice detail (right-side drawer, max-w-2xl) — replaced the inline fixed inset-0 ... slide-in-from-right pattern with <Drawer>.

Payslip detail (right-side drawer, max-w-md) — summary tile + Earnings/Deductions rows + "Open full payslip view" footer action.

Cleaned up an orphan </div>);} left over from the previous Discounts.tsx migration (commit 4f8c33f) — that dangling closure was a pre-existing TS error and is now fixed.

node scripts/lint-no-inline-modals.js → finance/*: 6 → 0 (StudentGroups, StudentGroupDetail, Invoices, Payslips all clean).
Whole-tree lint: only Messages.tsx and other out-of-scope files remain (already covered by other PRs).
npx tsc --noEmit for finance/* is clean except for two pre-existing errors that are not introduced by this PR: StudentGroup is exported from the store via a different path (consistency fix, deferred), and Trips.tsx:118 references Wallet without importing it (one-line import, deferred).