Add zoom steps and a larger start caption to the game link (#266)

The released game only ever zoomed in whole steps up to 400%, so a
small camera on a large screen stayed far smaller than it could be.
The "Click to play" caption was drawn in the 11 px panel title size
and was easy to miss.

- GAME_SCALE_STEPS gains 300%, 500% and 600%. The game tab picker,
  Auto in the editor and the game link all read the same list.
- The start caption takes its size from the new Theme.captionSize
  (16) instead of a constant in GameScreen.
- The player page keeps the default arrow cursor at all times. It no
  longer switches to the hand over the caption.

Tests:
- view.test: Auto for 320x180 in 2000x2000 is now 6, with cases
  for 3 and 5. play-settings.test takes 2.5 and 8 as invalid steps.
- e2e 60 checks the caption against the panel title size and the
  arrow cursor before and after the start. Module 03 follows the new
  step list.
- ./check.sh 2808 tests, CHECK EXIT 0 (before the last Theme tweak,
  which changes no test). Full e2e run ALL PASSED, 1574 checks.

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

tools/e2e/03-play.mjs

@@ -355,7 +355,7 @@ export async function play(t) {
     JSON.stringify(g),
   );
   g = await pickScale('Auto');
-  const auto = Math.max(0.25, ...[0.25, 0.5, 1, 2, 4].filter((step) => step <= fit));
+  const auto = Math.max(0.25, ...[0.25, 0.5, 1, 2, 3, 4, 5, 6].filter((step) => step <= fit));
   check(
     'auto takes the largest step that still fits',
     g.mode === 'auto' && g.factor === auto && g.label === `Auto · ${auto * 100}%` && g.frame.w === 640 * auto,

tools/e2e/60-release.mjs

@@ -7,7 +7,7 @@ const UPDATED = 'Release 60 updated';
 // Not a 16:9 multiple of the window on purpose: fitting it would need a scale between the steps.
 const CAMERA = { width: 300, height: 180 };
 /** The zoom steps of the game view (`GAME_SCALE_STEPS`); Auto takes the largest that fits whole. */
-const STEPS = [0.25, 0.5, 1, 2, 4];
+const STEPS = [0.25, 0.5, 1, 2, 3, 4, 5, 6];
 const RED = '#e0553f';
 const BACKGROUND = '#22252c';
 
@@ -206,6 +206,8 @@ export async function release(t) {
       title: await json('document.title'),
       editor: await json('typeof window.__gm'),
       running: await player('running()'),
+      captionHeight: (await player('screen()')).captionHeight,
+      cursor: await json(`getComputedStyle(document.querySelector('canvas')).cursor`),
     };
     check(
       'the link opens without a session: only the game, on the page colour, waiting for a click',
@@ -215,6 +217,13 @@ export async function release(t) {
         page.running === false,
       JSON.stringify(page),
     );
+    // The panel titles are 11 px; the caption is set at Theme.captionSize (16). The page keeps the
+    // arrow throughout – Pixi writes `default` as `inherit`, so read what the browser makes of it.
+    check(
+      '"Click to play" is set larger than the panel titles, under the arrow',
+      page.captionHeight >= 16 && ['auto', 'default'].includes(page.cursor),
+      JSON.stringify(page),
+    );
 
     // 60d. A click starts it in the start scene, zoomed to Auto: a whole number of pixels per unit.
     const size = { w: await json('innerWidth'), h: await json('innerHeight') };
@@ -240,6 +249,12 @@ export async function release(t) {
       JSON.stringify({ size, auto, screen, pixels, log: await player('log()') }),
     );
     await shot('60-release-playing');
+    const playingCursor = await json(`getComputedStyle(document.querySelector('canvas')).cursor`);
+    check(
+      'over a running game the cursor is still the arrow',
+      ['auto', 'default'].includes(playingCursor),
+      playingCursor,
+    );
 
     // 60e. The keys go to the game: the arrow moves the crate out of the middle, S stops the game.
     await holdKey('ArrowRight', 500);