docs(README): rewrite intro as positive framing

Drop the 'What this extension is not' negation list and absorb
its content into 'What this extension is' as positive descriptions
under five headings: a CMS for operators, a REST API, a Nostr
publisher, an order pipeline, and a single-tenant view of the
world (the last folds in customer-UI-lives-elsewhere, festivals-
are-external-NIP-51-lists, and per-restaurant-invoices-no-
splitter).

README.md

@@ -1,35 +1,51 @@
 # Restaurant — LNbits extension
 
-A Nostr-native restaurant CMS for LNbits. Restaurant owners enable this
+A Nostr-native restaurant CMS for LNbits. The operator (the person who
-extension on their LNbits account to build menus, manage modifiers and
+enables this extension on their LNbits account) builds menus, manages
-inventory, and watch orders in real time. Customer-facing UIs (kiosks,
+modifiers and inventory, watches orders in real time, and routes paid
-mobile, the AIO webapp) live elsewhere and connect via REST + Nostr.
+tickets to a thermal printer. Each restaurant's data is owned by that
+restaurant's wallet; menus are published to Nostr so any client — from
+a single venue's customer kiosk to a webapp aggregating dozens of
+restaurants for a festival — can subscribe and stay live.
 
 ## What this extension is
 
-- **A CMS** for one operator (one or many restaurants per LNbits wallet).
+**A CMS for restaurant operators.** One LNbits account can host one or
-- **A REST API** for menu read + order placement.
+many restaurants under the same login. Each restaurant carries its own
-- **A Nostr publisher** for menus (NIP-99 classified listings) and a
+profile, menu tree (categories → subcategories → items), modifier
-  Nostr inbound sync skeleton for orders (NIP-17 DMs).
+groups (required choices and optional addons, single- or multi-select),
-- **An order state machine** with print-job queueing and a Kitchen
+per-item availability windows, inventory, and Nostr identity.
-  Display screen.
 
-## What this extension is not
+**A REST API.** Public read endpoints serve menu trees and item
+details; gated write endpoints (admin key) handle CRUD; an unauthenticated
+order placement endpoint accepts carts and returns a Lightning invoice.
 
-- **Not a customer kiosk.** Customer-facing UI is the AIO webapp at
+**A Nostr publisher.** Menu items are published as NIP-99 classified
-  `~/dev/webapp`.
+listings (kind 30402, parameterized replaceable) every time they're
-- **Not a festival platform.** "Festival" / "collective space" /
+created or edited; restaurant profiles are kind 0 metadata; deletions
-  "food court" are emergent — a curator publishes a NIP-51 list of
+are NIP-09. Tags carry structured price, dietary flags, allergens, and
-  restaurant pubkeys, the webapp aggregates from that list. The
+ingredients so subscribers can filter without parsing markdown.
-  extension itself only ever knows about its own restaurant.
+
-- **Not a payment splitter.** Per the design discussion: each menu
+**An order pipeline.** Every cart placed against this restaurant
-  item belongs to one restaurant, each restaurant issues its own
+becomes one order with snapshotted line-item prices and selected
-  invoice, and the customer pays N invoices to complete a multi-
+modifiers. The invoice listener settles `pending → paid` on payment;
-  restaurant cart. The webapp pre-flights the total via
+the operator (or auto-accept) walks it through `accepted → ready →
-  `POST /api/v1/orders/quote` to confirm sufficient balance before
+completed`. Stock decrements on settlement, a print job lands in the
-  opening any per-restaurant invoice. If a payment ever fails after
+queue, and the Kitchen Display picks it up.
-  another succeeded (rare on internal LNbits transfers), the
+
-  customer settles the remainder in person.
+**A single-tenant view of the world.** Customer-facing UIs (kiosks,
+mobile apps, the AIO webapp at `~/dev/webapp`) live outside this
+extension and connect via REST and Nostr. When a customer wants to
+order across multiple restaurants — at a festival, in a collective
+space, across a food court — that grouping is curated externally
+(typically as a NIP-51 list of restaurant pubkeys), the webapp fetches
+each menu independently, builds a unified cart, and sends one order
+per restaurant. Each restaurant issues its own bolt11 invoice; the
+customer pays N invoices to complete the cart. No central wallet
+holds the float, no splitter divides the payment, and each operator
+sees their own sats land directly. The webapp pre-flights the total
+via `POST /api/v1/orders/quote` so a customer with insufficient
+balance gets one clean error rather than a partially-paid cart.
 
 ## Architecture