Resolve share URLs from the instance host and ship 1200×630 Open Graph images.

Staging no longer advertises production canonicals, and Slack/social previews get a default hero card with template and article overrides.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/guides/static-assets.md

@@ -11,7 +11,7 @@ public/
     icons/              # UI chrome (close, help) + FeatureGrid card glyphs
     logos/              # Brand + social lockups
       partners/         # Logo wall partner SVGs (kebab org slug)
-    marketing/          # Hero, feature panels, section numbers, avatars, banners, book cover
+    marketing/          # Hero, OG share images, feature panels, section numbers, avatars, banners, book cover
     case-study/         # CaseStudy card SVG artwork (canonical)
     shapes/             # Decorative ornaments (stats, quotes, unions, content shapes)
     vector/             # Use-case group marks
@@ -40,7 +40,8 @@ Do not duplicate the same glyph in both places unless migrating between systems.
   `/assets/...` strings in components.
 - **Blog art** stays under `public/content/blog/` with
   `{slug}-vertical.svg`, `-horizontal.svg`, `-section.svg`, `-tag.svg`,
-  and `-ornament-right.png` / `-ornament-left.png` (body gutter shapes).
+  `-og.png` (1200×630 share image), and `-ornament-right.png` /
+  `-ornament-left.png` (body gutter shapes).
 - **Favicon** reuses `assets/logos/community-rule.svg` (`ASSETS.LOGO` in
   `app/layout.tsx` metadata) plus generated root binaries for Safari/iOS:
   `public/favicon.ico`, `favicon-16x16.png`, `favicon-32x32.png`, and
@@ -66,6 +67,9 @@ stage. Raster → SVG conversion is tracked in
 | `marketing/section-number-*.svg` (×3) | SectionNumber | **Done** — SVG |
 | `marketing/avatar-*.svg` (×3) | Avatar / ASSETS | **Done** — SVG |
 | `marketing/hero-image.png` | HeroBanner | **Design review** — likely keep raster |
+| `marketing/og-image.png` | Default `og:image` / `twitter:image` | **Done** — 1200×630 hero crop (`ASSETS.OG_IMAGE`; `npm run generate:og-images`) |
+| `marketing/og-image-templates.png` | Templates `og:image` | **Done** — 1200×630 (`ASSETS.OG_IMAGE_TEMPLATES`) |
+| `content/blog/*-og.png` | Article `og:image` | **Done** — 1200×630 from `{slug}-section.svg` (`contentBlogOgPath`) |
 | `marketing/communityrules-cover.svg` | About / Book | **Done** — Structure Before Crisis cover (`ASSETS.STRUCTURE_BEFORE_CRISIS_COVER`; Figma **22137:891197**) |
 | `marketing/community-rules-cover.png` | About / Book | **Done** — Community Rules (2021) cover (`ASSETS.COMMUNITY_RULES_COVER`; gitignore exception) |
 | `marketing/governance-booklet.pdf` | About / Book | **Done** — Community Rules (2021) PDF (`governanceBookletPath()`) |