chore: groundwork for SEO fixes and tech&vis debt

docs/design/change-list.md

@@ -1,4 +1,18 @@
-# Change list for implementation (status after pass 2; SEO round drawn)
+# Change list for implementation (status after pass 2; SEO round drawn; cleanup round drawn)
+
+## Cleanup round
+
+1. Editor: site and authors, "Create author" states (4 states, desktop and mobile): the mobile dialog sat under the Details sheet (z-index 50 against 55) and was hidden. It now stacks above the sheet (z-index 60), as the SEO panel does. Full-width bottom sheet with grabber, same fields, Cancel left and "Create author" right (Cancel below on mobile, as the other mobile dialogs). Frame: `DirectoryFrame.dc.html`. The four states share the fix: dialog, "for me", slug taken, failed.
+2. Integration, "6. Errors": the 403 row gets the muted note "Site SEO defaults are owner only. Article SEO fields need only the right to edit the article." The row below shifts down by the wrapped note height (two 18 px lines desktop, three mobile, plus the 2 px row gap). The old inline parenthetical with the same sentence in the 403 cause text was removed, so it isn't said twice. Frame: `IntegrationPage.dc.html`.
+3. Integration, sitemap errors: 404 now shows the body `site_not_found` in code style (was "Site not found"); 400 now shows the generic body-mismatch text used by the other routes (was "Invalid page or size.").
+4. New groups on the Back-office board: "Sites: pagination" and "Authors: pagination", 10 states each (20 states, every one desktop and mobile; light and dark by the theme switch). Back-office total 409 → 429. Same pager as Articles and Media, sizes 5, 25, 50, 100, default 25 (no difference to report). One deviation: on a single page the page-size select is hidden and only "N sites" or "N authors" remains.
+5. Specs: screens/sites.md, screens/authors.md (pager states, URL rules, out-of-range fallback), screens/integration.md, states.md (pagination states, three HTTP rows), components.md (single-page variant, no new component), routes.md (Sites pagination in the URL).
+
+**Backend assumptions to confirm.** GET /v1/site/ takes `q`, `page`, `size` and returns `X-Total-Count` (it returns every site today). GET /v1/author/ gets `page`, `size` and `X-Total-Count` (it has `q`).
+
+**Open points.**
+- Sites has no search field. The two states that need one (empty after search, search resets to page 1) draw the Authors field on Sites with "Search by name or key". Drop those states if you don't want search on Sites.
+- Stale copy found, not changed: GET /v1/article/ on Integration still shows the 400 caption "Invalid page or size." while every other route, and now the sitemap, uses the body-mismatch text. The 404 row of the Errors table still lists only the four resource messages and doesn't mention `site_not_found`. The existing Sites and Authors "Default" frames don't draw the count line. README.md state counts and the "Pagination" notes were not updated (outside this round).
 
 ## SEO round: decisions (frames drawn)