Keep search, facets, and sort in the page URL.

CONTENT-WP-0002-T04 writes q, facet values, and sort into history so back and forward restore the table.

Assistant: grok
Assistant-Session: 01a1346c-fdff-7741-b1af-b7283661554b

workplans/CONTENT-WP-0002-ui-extraction.md

@@ -16,7 +16,7 @@ state_hub_workstream_id: "55c1d92f-fe1a-552a-998d-2d6905fb6b99"
 
 # UI extraction and experience skeleton
 
-Deliver the strongest OnCo-style interaction patterns on generic data. CONTENT-WP-0000 and CONTENT-WP-0001 are finished, so this plan is eligible. T01 through T03 have landed under `ui/`. T03 maps each record to a generic browser row and renders the columns named by that kind's manifest view. T04 is next. See `workplans/evidence/CONTENT-WP-0002-ImplementationNotes.md`.
+Deliver the strongest OnCo-style interaction patterns on generic data. CONTENT-WP-0000 and CONTENT-WP-0001 are finished, so this plan is eligible. T01 through T04 have landed under `ui/`. T04 keeps search, facet selection, and sort in the page URL, and back and forward restore that view. T05 is next. See `workplans/evidence/CONTENT-WP-0002-ImplementationNotes.md`.
 
 ## Work packages
 
@@ -51,7 +51,7 @@ state_hub_task_id: "f3ccb974-153a-5dae-aa52-7a985175ca52"
 
 ```task
 id: CONTENT-WP-0002-T04
-status: todo
+status: done
 priority: high
 state_hub_task_id: "bacd58df-4834-5157-834e-26da4c6ba470"
 ```

workplans/evidence/CONTENT-WP-0002-ImplementationNotes.md

@@ -63,4 +63,19 @@ Checks on 2026-10-13, after T03:
 - `npm run typecheck`, `scripts/check_ui_boundary.py`, fixture validation, and the contract and ingest tests passed.
 - `next dev` on `127.0.0.1:3400` returned the home table with a Kind column, and the concept and pattern indexes with Tags (`regulation`, `translation`). The server was stopped. No browser pane was available.
 
-Not done: URL facets and sort, keyboard search and empty/error states, the T06 gate for search and filter, the formal import gate, the provenance gate, or keyboard and small-screen smoke. Facet values are on the row for T04; they do not filter the table yet.
+Not done after T03: URL facets and sort, keyboard search and empty/error states, the T06 gate for search and filter, the formal import gate, the provenance gate, or keyboard and small-screen smoke. Facet values were on the row; they did not filter the table yet.
+
+## T04 — shareable query, facets, and sort
+
+The query string follows the pinned table shape: `q` is the search text, a facet key repeats for each selected value (`tags=regulation&tags=structure`), and `sort` is the column key with a leading `-` when descending. The default sort is omitted. Search is written when the form is submitted. A facet button or a sort button writes immediately. Each write is a history entry.
+
+`applyTableView` filters, then sorts. Within one facet, any selected value matches. Every selected facet key must match. Search looks at the name, the summary, and facet values.
+
+Checks on 2026-10-13, after T04:
+
+- `npm test` in `ui/`: 14 tests passed. The view tests round-trip a query and filter rows. The history test submits a search, selects a tag, reverses the sort, then goes back to the unfiltered table and forward to the sorted tag view.
+- The same test dispatches `popstate` on `window` after `pushState` and checks that the history reader reports the new query.
+- `npm run typecheck`, `scripts/check_ui_boundary.py`, fixture validation, and the contract and ingest tests passed.
+- `next dev` on `127.0.0.1:3400` rendered `/systems-thinking/concept/` with the search field and the tag `regulation`. The server was stopped. No desktop browser was available, so back and forward were exercised in the history test rather than in a graphical browser.
+
+Not done: keyboard search and empty/error/loading states, the T06 gate for both dataspaces across search and filter, the formal import gate, the provenance gate, or keyboard and small-screen smoke. A facet key other than `tags` still has no values in these fixtures.