[Plugin] Previous/Next paging and a page position on both admin lists

.changeset/prev-next-and-page-of.md

@@ -0,0 +1,94 @@
+---
+"@otta-sh/admin-presentation": patch
+"@otta-sh/admin-react": patch
+---
+
+Previous, Next and `Page N of M` on the two React lists.
+
+The Orders and Pricing & inventory lists now carry a pager beside `Load more`.
+`Next` moves forward one page and `Previous` moves back one, both exactly — the
+console keeps the cursors it has already been handed and replays one to go back,
+so there is no new query, no reverse keyset read, and nothing new on the wire.
+
+`Previous` re-requests the page rather than restoring the rows it had in hand.
+The stack holds cursors, not pages: a request under a token the service already
+issued answers with the collection as it stands now, agrees with a reload of the
+same address, and does not grow without bound down a long scan.
+
+**The two ways forward are two acts, not two spellings of one.**
+`Previous`/`Next` move a one-page window; `Load more` extends it and keeps the
+rows above. Both advance the same position, so the page number counts either.
+Paging on from an accumulated scan therefore continues from where the scan
+reached and shows that page alone — which `Next` says in front of the click
+rather than leaving to be discovered after it. While several pages are on
+screen the position states the window it describes (`Pages 2–3 of 6`), because
+"Page 3" over fifty rows beginning at page two tells whoever is reading the top
+of that list the wrong number.
+
+**The page count is derived from what the list already holds.** The service
+counts the filtered set alongside the page it returns and the plugin states the
+page size it pages by, so the count is arithmetic over two values already on
+screen — never a second request. It consumes the figure the count line actually
+stated rather than the raw payload number, so a total the caption withheld
+cannot reappear underneath it; the two lines can still drift if the store
+changes between the count and the page, but only for that reason. A service that
+reports no total leaves an em dash rather than a guess — absent is not one, and
+it is not zero. A render standing on the last page states that page as the
+count; where the arithmetic insists there are more pages than the one being
+stood on, the two disagree outright and it states neither.
+
+**The stack resets whenever the filter does**, in the address bar as well as in
+memory: a cursor is only meaningful against the predicate it was issued under,
+so a stack that survived an apply would offer to step back into the set the
+operator just left.
+
+**Returning to page one is page one**, whatever asked for it. A request that
+carries no cursor comes back as the first page under the current predicate, so
+it may state the whole set without a hedge, it gets the empty-collection words
+rather than the page-scoped ones when it comes back empty, and on Pricing &
+inventory it may both raise and clear the banner that says the low-stock
+threshold could not be read. Only a page reached WITH a cursor carries that
+banner forward, because such a request reports the filter as available by
+contract and so has no answer of its own.
+
+**Paging survives the browser's own Back and Forward, and a drill-in.** The
+address carries one cursor, which is what makes a link shareable; the history
+entry carries the walk behind it, which a link must not. Without that, a Back
+onto a page an operator had walked to came back as though it had been pasted in
+— position unknown, `Previous` unavailable, two presses into a scan. The entry a
+record's drill-in pushes carries it too, so opening an order from page two,
+reloading, and pressing `Back to orders` returns to a list that still knows
+where it is. Returning to page one deliberately pushes an entry, as any other
+page does; only the recovery from a page that would not open still corrects the
+entry in place.
+
+**A page nothing holds a record of cannot know its own number.** The position
+reads `Page — of 6` and `Previous` is offered dimmed, carrying the reason: the
+page before this one is not known here. It states that ignorance and not how the
+operator arrived, which a reload, a bookmark and a link all reach identically.
+Paging forward from such a page still comes back to it, and a link to the LAST
+page keeps its pager rather than vanishing at the moment it is the only thing
+that could say where the operator is.
+
+Where paging has stopped — a page that failed, or a continuation the service
+refused mid-scan — the whole pager is withdrawn along with `Load more`, and the
+rows stay exactly where they are. A failed page never clears the rows now,
+whichever direction it was asked for; the refusal is drawn beside them, and its
+wording names no direction, because three controls produce it and only one of
+them is "more".
+
+On Pricing & inventory, a page reached with `Next` or `Previous` keeps the
+banner raised when the low-stock threshold could not be read. Every request
+carrying a cursor reports the filter as available by contract — the predicate
+rode inside the token — so treating that as an answer would drop the banner at
+the click of a control that has nothing to do with filtering, and start
+captioning the whole catalogue as low stock.
+
+The controls are dimmed with `aria-disabled` rather than disabled outright, so
+they keep their place in the tab order and their visible focus ring: pressing
+`Next` onto the last page would otherwise take the control out from under the
+operator's focus. The reason a control is dimmed is exposed as an accessible
+description rather than only as a tooltip. The unavailable state is drawn as a
+flat fill, a lighter border and a muted label rather than as a blanket opacity —
+enough to read as "off" at a glance, and not so much that the word on it becomes
+work to read.

packages/admin-presentation/src/index.ts

@@ -114,11 +114,20 @@ export {
 	APPLY_FILTERS_LABEL,
 	CLEAR_FILTERS_LABEL,
 	LOAD_MORE_LABEL,
+	NEXT_AT_END_TITLE,
+	NEXT_PAGE_LABEL,
+	NEXT_RELEASES_SCAN_TITLE,
 	NOTHING_ON_PAGE,
+	PAGER_LABEL,
 	PAGE_SCOPED_SUFFIX,
 	PAGE_ZERO,
+	PREVIOUS_AT_START_TITLE,
+	PREVIOUS_PAGE_LABEL,
+	PREVIOUS_UNWALKED_TITLE,
 	SCAN_FURTHER,
 	listOutcome,
+	pageCount,
+	pagePositionLine,
 	rowCountLine,
 	type ListOutcome,
 	type ListOutcomeOptions,
@@ -152,7 +161,7 @@ export {
 	ORDERS_BACK_LABEL,
 	ORDERS_EMPTY,
 	ORDERS_LIST_INTRO,
-	ORDERS_LOAD_MORE_FAILED_TITLE,
+	ORDERS_PAGE_FAILED_TITLE,
 	ORDERS_NO_MATCH,
 	ORDERS_NOUN,
 	ORDERS_SEARCH_LABEL,
@@ -213,7 +222,7 @@ export {
 	PRODUCTS_BACK_LABEL,
 	PRODUCTS_EMPTY,
 	PRODUCTS_LIST_INTRO,
-	PRODUCTS_LOAD_MORE_FAILED_TITLE,
+	PRODUCTS_PAGE_FAILED_TITLE,
 	PRODUCTS_LOW_STOCK_NOUN,
 	PRODUCTS_LOW_STOCK_NO_MATCH,
 	PRODUCTS_NOUN,