Hero Phase 4: moon/badge/image elements + resize + snap grid

Final phase of the hero canvas editor (see HERO_EDITOR.md) — v1 complete.

- element tray adds moon, badge, and image; property panels:
  - moon: size / glow / color
  - badge: text / background / text color / corner radius
  - image: upload (/admin/uploads, >1MB warning) / width% / alt
- corner resize handle on selected elements (image→width%, moon→size,
  text_block→box width)
- 8px snap-grid toggle with a faint canvas grid overlay; drag snaps when on
- HeroElement: image element shows an "Upload an image" placeholder until a
  source is set (a srcless image never ships live)

Verified in-browser: all five element types add + edit; moon resized 64->104px
via the handle; snap grid overlays; a published moon + badge render on the live
portal; no console errors.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

website/HERO_EDITOR.md

@@ -115,8 +115,16 @@ layout adapts across viewports without breakpoint data. `version` is validated
   add/remove lines, align) and buttons editor (label/path/variant, add/remove).
   Verified: select shows the line editor, editing a line updates the canvas live,
   drag moved 50%→65%, add→3/delete→2 elements, empty-canvas click deselects.
-- **Phase 4 — moon + badge + image + resize + snap grid.** Remaining element types,
-  resize handles, 8px snap. *Exit:* place a moon and an uploaded image, resize, publish.
+- **Phase 4 — moon + badge + image + resize + snap grid** ✅ (verified 2026-06-28).
+  Tray adds moon/badge/image; property panels (moon: size/glow/color; badge:
+  text/colors/radius; image: upload/width/alt); corner resize handle (image→width%,
+  moon→size, text→box width); 8px snap-grid toggle with overlay; image placeholder
+  until a file is chosen. Verified: each type adds + edits, resize moved a moon
+  64→104px, snap grid shows, and a published moon+badge render on the live portal.
+
+**Status: v1 feature-complete.** All phases verified end-to-end; ready for PR.
+Deferred (noted in the design doc as follow-ups): 8-point resize (only a corner
+handle for now), per-viewport layouts, server-side image compression.
 
 ## 8. Edge cases (from the doc, carried forward)
 - `JSON.parse` wrapped in try/catch + `version` check → fall back to `DEFAULT_LAYOUT`.