[djthorpe]

Adds the pieces every server's frontend needs for its lists. They were first written in an app built on this package, and used there for about ten lists.

Module	What it has
/api	request, a JSON request, beside requestStream. It throws an ApiError when the response isn't ok, and returns undefined for an empty body.
/list	ListController: a list an API returns a page at a time ({ count, body })
/list/view	gs-table: a Carbon data table of a list's page
/list/tiles	gs-tiles: a row of tiles of a list, with an optional "all" tile first, of which one is chosen. It fires gs-tile-select with the tile's value.
/router	Router: shows the page of the location's hash, with parameters (#database/shop)

ListController:

• Pages, sorted by the server.
• reset for when a filter changes.
• It follows a ChangesController's changes to its tables, and is unavailable while the server can't be reached.
• It keeps the open item current, or closes it on a 404.

gs-table:

• A column with a sort key sorts the list when its header is clicked. Carbon's own sorting, which only sorts the rows on the page, is turned off.
• Pagination, and a skeleton until the first page loads. The skeleton always has a header, because Carbon's re-renders forever without one.
• Rows open their items.

Also:

• Docs: README sections on lists and routing, with examples.
• Tests: for request, ListController (load, last page, reset, sort, the open item, errors) and parseRoute. 42 pass.
• Dependencies: lit and @carbon/web-components stay optional peer dependencies, needed only by the views.

The app's header and side navigation, and a helper that opens a list's item in a panel, stay in the app until a second app uses them.

[Copilot]

🟡 Changes recommended

Unresolved issues allow stale responses to overwrite pagination, filtered results, and selection, leave newly created lists incorrectly available during outages, and prevent keyboard-only users from opening items.

4 open issues

• Initialize availability from the current connection state · New
• Ignore stale list responses after state changes · New
• Avoid restoring a stale selection after reload · New
• Provide keyboard-accessible controls to open table items · New

What changed in this PR

This PR expands the TypeScript package with reusable list controllers and views, JSON requests, and hash-based routing for server frontends.

Changes:

• Adds paginated, server-sorted lists with change-stream integration and selected-item refresh.
• Adds Carbon table and tile views, plus a hash router with route parameters.
• Exports the new modules and adds documentation and tests.

File	Description
frontend/​test/​router.test.ts	Tests route parsing and parameter decoding.
frontend/​test/​request.test.ts	Tests JSON requests, errors, and empty responses.
frontend/​test/​list.test.ts	Tests list loading, pagination, sorting, selection, and errors.
frontend/​src/​router/​router.ts	Implements hash parsing and page visibility routing.
frontend/​src/​router/​index.ts	Exports the router API.
frontend/​src/​list/​view.ts	Adds the sortable, paginated Carbon table view.
frontend/​src/​list/​tiles.ts	Adds selectable tiles with selection events.
frontend/​src/​list/​index.ts	Exports the list controller and types.
frontend/​src/​list/​controller.ts	Manages list pages, sorting, selection, and change updates.
frontend/​src/​api/​request.ts	Adds the JSON request helper.
frontend/​src/​api/​index.ts	Exports the request helper and options.
frontend/​README.md	Documents lists, views, and routing with examples.
frontend/​package.json	Exposes list and router package entry points.

_{Review effort: Balanced}