feat(map-editor): v0.2.0c.4 — G-toggle mode-aware world overlay

Adds a G key that toggles the world-space overlay on and off
(default on). The overlay adapts to the active painting mode:

- Auto-Tile mode shows the map-grid (paint-tile boundaries, which
  sit at half-tile offsets from the render-cell boundaries in
  dual-grid), the per-map-tile vertex dots, and the snapped
  paint-target highlight.
- Direct mode shows only a subtle render-cell grid, since LMB
  strokes write directly to render-cells in that mode.

Bumps the lib-core.maps dep pin to 0.5.6 to pick up the dual-grid
bitmask fix that makes the auto-tile output match the dual-grid
mental model.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

manifest.module

@@ -1,6 +1,6 @@
 {
     "id": "map-editor",
-    "version": "0.2.0c.3",
+    "version": "0.2.0c.4",
     "kind": "module",
     "api": "^0.1",
     "ci_frames": 30,
@@ -9,7 +9,7 @@
         "blob_rect_stone": "lib-asset.prototype-blob-geom"
     },
     "deps": [
-        {"id":"lib-core.maps","version":"0.5.5"},
+        {"id":"lib-core.maps","version":"0.5.6"},
         {"id":"lib-core.render","version":"0.1.0"},
         {"id":"lib-core.camera","version":"0.3.0"},
         {"id":"lib-core.input","version":"0.4.0"},