Drop the collider and delete-node buttons from the inspector

Adding a collider now lives only in the Scene objects context menu, deleting a node on
the Delete key and the node context menu. The e2e checks that pinned the inspector button
now drive the hierarchy menu instead, including that its entry is disabled on template
content and on a placed container without raising a notice.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -351,8 +351,8 @@ inspector below X/Y/Z, undoable, with ↺ back to 0. It belongs to the placed ob
 
 A **collider** is an asset (`shape` box/circle, `width`/`height` or `radius`) placed like any
 other object – typically as a child of the sprite it belongs to, so its position is the offset
-from that *body* and it moves with it. Right-click an object in **Scene objects** (or press
-**+ Add collider** in its inspector) to get one with one click: a box collider sized like the
+from that *body* and it moves with it. Right-click an object in **Scene objects** → *Add
+collider* to get one with one click: a box collider sized like the
 sprite, parented at its centre. Colliders can be reused across objects, overridden per instance
 and stacked (hitbox + hurtbox on one sprite; colliders of the same body never collide with each
 other). They are editor symbols: green outlines in edit mode, invisible in play mode.
@@ -644,7 +644,7 @@ npm run check        # typecheck + lint + format:check + tests, what CI would ru
                      #   code is lost (tail's is reported), so a red run reads as green
 npm run build        # writes dist/ and regenerates index.html
 export GM_REMOTE=user@host                                    # optional: run the browser elsewhere; see below
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 535 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 537 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 – a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result