Replace Create-rule header portraits with real PNGs so the circles paint.

The old SVG wrappers nested corrupt PNGs, so browsers fetched the files but showed empty rings.

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

docs/guides/static-assets.md

@@ -65,7 +65,7 @@ stage. Raster → SVG conversion is tracked in
 | `marketing/feature-*.svg` (×4) | Mini cards | Panel art (`support`, `exercises`, `guidance`, `tools`) |
 | `icons/icon-{git-branch,arrow-left-right,door-open,message-square-share}.svg` | FeatureGrid | Card glyphs from Figma Section/Feature-Grid (18632:10668) |
 | `marketing/section-number-*.svg` (×3) | SectionNumber | **Done** — SVG |
-| `marketing/avatar-*.svg` (×3) | Avatar / ASSETS | **Done** — SVG |
+| `marketing/avatar-*.png` (×3) | Avatar / ASSETS | **Done** — PNG portraits (not SVG wrappers) |
 | `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`) |