[github-actions]

Games can run in a web page. The core (scratch) no longer depends on LWJGL: the window,
OpenGL, sound and image decoding come from a platform module. scratch-desktop is the desktop
one (LWJGL, as before) and scratch-web the browser one: org.openpatch.scratch.web.export.WebExport
compiles a game and the library to WebAssembly with TeaVM and writes a page that runs it.
The fat jar (scratch-<version>-all.jar) contains the core and scratch-desktop, so programs that
use it change nothing. Maven projects that depend on scratch alone now also need scratch-desktop.
Text is drawn by a Java port of stb_truetype, pixel for pixel as before, on every platform.
Tiled maps work in a web page too: scratch-tiled reads .tmx and .tsx files itself and no longer
depends on Jackson (maps load exactly as before; checked on 78 maps and tilesets). TiledMap.spawn
takes the sprite classes it may make, map.spawn("Objects", Player.class, Wall.class), instead of
looking classes up by the type names in the map, which a web page cannot do. NRW projects get
their own web jar, scratch-<version>-nrw-web.jar.
Saving needs no Jackson either: SaveData and File read and write JSON themselves (the same
rules as before: public fields, unknown or mistyped values are refused by SaveData). In a web
page, saves are kept in the browser's storage for that page. File.saveXML, File.loadXML and
File.loadXMLOrCreate are gone: use File.save and File.load (JSON). The web jar contains every
extension but gamepad.

Compatibility artifacts and catalogs are prepared for 7.1.0. Before merging, review the browser policy and synchronize openpatch/online-ide from this release branch:

scripts/sync-online-ide.sh /path/to/online-ide

The script also verifies the checkout. Commit and push the browser updates in online-ide and run its browser compatibility tests (npm run test:browser) before merging this PR. RELEASING.md has the full cross-repository runbook.