chore: grounwork for SEO features

docs/design/change-list.md

@@ -1,4 +1,50 @@
-# Change list for implementation (status after pass 2)
+# Change list for implementation (status after pass 2; SEO round drawn)
+
+## SEO round: decisions (frames drawn)
+
+**Placement.** A "Search and sharing" section sits under "Site and authors" in the Editor sidebar and in the mobile Details sheet. It is collapsed by default, shows a one-line summary ("Ready", "2 suggestions" or "Hidden from search") and is remembered per browser like Site and authors. It holds only the slug, the full URL and three actions: "Edit search and sharing", "What the frontend gets" and the suggestion list. The fields and live previews open in a slide-over (desktop) or a 92% bottom sheet stacked over the Details sheet (mobile), because the 280 px sidebar is too narrow for previews and the slide-over rule already covers forms with a live preview. The API preview is a 720 px dialog (desktop) or a bottom sheet (mobile).
+
+**Principles.** RenewCMS does not render pages or inject meta tags. Every field is optional and the UI shows its fallback. No scores. Suggestions never block saving or publishing; publishing is allowed regardless. Suggestions are dismissible per article.
+
+**Fallback chain (resolved server-side, shown in the UI).**
+| Output | Order |
+|---|---|
+| title | seo_title, then article title; site title_template applied last |
+| description | seo_description, then excerpt, then first sentence of the body, then site default_description |
+| image | og_image_id, then cover_image_id, then site social image |
+| canonical | canonical_url, then site base_url + "/" + slug |
+| robots | noindex true gives "noindex, nofollow"; otherwise site default_robots |
+| og/twitter title and description | social_title, social_description, then the resolved values above |
+
+**Soft ranges (counters, never blocks).** Meta title 30–60 characters; description 70–160; slug "very long" above 75 characters. Counter turns neutral-warning (`--ui-warning`) outside the range, never red.
+
+**New article fields (PATCH /v1/article/{id}, all optional, snake_case).** `slug`, `excerpt` (max 300), `seo_title` (max 120), `seo_description` (max 320), `cover_image_id`, `cover_image_alt` (max 200; the cover is "ready" only with alt text), `social_title`, `social_description`, `social_image_id`, `canonical_url` (absolute https URL), `noindex` (boolean; only sets a flag in the API, it doesn't change visibility), `seo_dismissed` (string[] of suggestion codes). Slug: lowercase letters, numbers, hyphens; unique per site; 409 `slug_taken` with `suggestion` ("<slug>-2"); auto-generated from the title until edited.
+
+**New site fields (PATCH /v1/site/{id}, owner only).** `site_name`, `title_template` (default "%title% | %site%", must contain %title%), `default_description` (max 320), `social_image_id` (existing), `default_robots` ("index" | "noindex"; existing as robots).
+
+**New endpoints.**
+- `GET /v1/article/{id}/seo`: resolved object, public for online articles, 404 for drafts to anonymous callers. Shape: `{ title, description, canonical_url, robots, og: { type, title, description, image, image_alt, url, site_name, locale }, twitter: { card, title, description, image, image_alt }, image: { url, alt, source }, authors: [{ name, url, same_as: [] }], published_at, modified_at, fallbacks: { title, description, image, canonical }, json_ld }`. `json_ld` is a ready Article object (headline, description, image, author[] with name, url and sameAs from author profile URL and social links, datePublished, dateModified, mainEntityOfPage).
+- `GET /v1/site/{key}/sitemap?page=&size=`: published URLs only, total in `X-Total-Count`. Items: `{ url, modified_at, noindex }`. Decision: yes, shown on Integration under "Search and sharing" with a copy button; noindex articles are included with the flag so the frontend can skip them.
+- `GET /v1/article/?seo=ready|suggestions|hidden`: filter behind "Needs attention" (suggestions) with `seo_status` and `seo_suggestions` (count) added to list items.
+
+**Articles list.** Quiet indicator inside the Status cell (and under the title on mobile cards): nothing when ready, a lightbulb chip "N" for suggestions, an eye-off chip "Hidden" for noindex. Toolbar gets a "Needs attention" toggle next to search; tabs and counts are unchanged. It behaves the same on a single-site install (independent of the Site filter, which stays hidden).
+
+**Authors.** No change to the Authors screen. Profile URL (website) and social links feed `authors[].url` and `same_as`, and JSON-LD `author[].sameAs`; the API preview shows them.
+
+**Permissions.** Anyone who can edit an article edits its SEO fields. Only the owner edits site SEO defaults. 401 and 403 rows join the existing HTTP table: 403 `owner_only` on Site SEO fields, 401 on a missing session.
+
+**Left out on purpose.** Keyword scoring and focus keywords, readability scores, redirects management, schema types beyond Article, hreflang, robots.txt and sitemap rendering (RenewCMS only provides data), automatic image generation for social cards.
+
+**Open questions.**
+1. Is `slug` immutable after first publish, or can it change (and break URLs with no redirects)?
+2. Does the API return the SEO object for drafts to authenticated callers (for frontend previews)?
+3. Should noindex articles be excluded from the sitemap endpoint instead of flagged?
+4. Is title_template applied by the API (resolved title) or only returned for the frontend to apply?
+5. Backfill: generate slugs for existing articles from their titles at migration, with `-2` suffixes on conflicts?
+6. Should excerpt be exposed in the list payload as the article teaser?
+
+**Status.** Frames drawn on the Back-office board (groups: Articles: search status, Editor: search and sharing, Editor: what the frontend gets, Sites: SEO defaults), Integration page group added, specs updated. Placement rationale: the sidebar holds only the summary, address and suggestions because it is 280 px wide; previews and fields need a slide-over.
+
 
 Ordered by implementation dependency: tokens and shell first, then shared components, then screens. "Frontend only" means no backend work is needed.