Open a scene framed, and thin out two inspector sections (#295)

Three small things asked for in one issue. A scene came up wherever
the view happened to stand, and the inspector carried a button and a
list that are better reached somewhere else.

- A scene comes up framed as if Fit had been clicked: after a
  project is loaded and when another scene is opened. From then on
  the view belongs to the user.
- An empty scene has nothing to frame and stands at the origin, one
  pixel per unit. A scene the running game loads is not framed anew.
- The Container tab is left out. It keeps the view of each container
  as before (#171).
- The Unpack button and the two lines under it are gone from the
  inspector of a placed container. Unpack container stays in the
  right-click menu of the hierarchy and of the scene view.
- The corners of a polygon collider are no row in the inspector any
  more. They are edited on the outline in the scene view. The new
  schema option noRow keeps a property out of the inspector while it
  stays a property.

Tests:
- Gate on melektaus-atx: 219 files, 3401 tests, CHECK EXIT 0.
- One new unit test in tests/core/polygon.test.ts: the corners are
  a property of the collider and no row.
- Three new e2e checks: a loaded project is framed like Fit (module
  03), an opened scene is (04), and after a real reload a click on
  Fit moves nothing (09).
- Module 09 unpacks through the right-click menu now and checks that
  the inspector offers no button.
- Full suite on melektaus-atx: 1695 checks, all pass. Smokes 24, 19
  and 21, all pass.
- No counter-probe evaluated, and nothing looked at after the build.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -45,7 +45,7 @@ npm run build        # writes dist/ and regenerates index.html; the folder is wh
 The browser suite and the three example games need a machine with a GPU:
 
 ```bash
-node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 1692 checks (GM_STEPS=20 for one step)
+node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 1695 checks (GM_STEPS=20 for one step)
                                                    #   every tool signs in first – see the Accounts page
 node tools/seed-jumprun.mjs && node tools/smoke-jumprun.mjs
 node tools/seed-tetris.mjs && node tools/smoke-tetris.mjs