Add TigerModal — in-app confirm/prompt/alert house primitive

[WebTigers]

Why

The house rule bans the browser's native confirm()/prompt()/alert() (unstyled, un-themeable, freeze the tab) — but there was no shared in-app replacement, so modules hand-rolled their own: TigerStripe's PayDialog and TigerLicense's Dialog are the same helper written twice. This promotes it to a core theme primitive next to TigerButton/TigerDOM.

API

TigerModal.confirm({ title, body, confirmLabel, cancelLabel, variant }) // -> Promise<boolean>
TigerModal.prompt({ title, label, value, placeholder, help, confirmLabel, variant }) // -> Promise<string|null>
TigerModal.alert({ title, body, confirmLabel, variant }) // -> Promise<void>

prompt resolves null on cancel, mirroring window.prompt so if (v === null) return; swaps straight in. Promise-based, themed, and it builds one reusable Bootstrap modal on demand (like TigerDOM.notify builds its alert) so a view needs no modal markup. Enter submits; field focuses on open; a confirm settles before hide so the trailing hidden.bs.modal no-ops.

Wiring

tiger.modal.js enqueued after bootstrap.bundle in all three layouts (public / admin / auth) — depends only on bootstrap.Modal, never jQuery/TigerDOM (the public layout doesn't even load TigerDOM). Documented in AGENTS.md's UI/UX section.

Follow-up

Once this releases and lands on the boxes, TigerStripe (PayDialog) and TigerLicense (Dialog) migrate to TigerModal, retiring their local copies.

🤖 Generated with Claude Code