Migrations

The breaking changes, renames, and behavior shifts for every envapt major-version upgrade.

Each guide covers one major-version jump and the changes to expect when you take it.

v7 to v8. The source classes get shorter names, one universal envapt import replaces the workerd and browser subpaths, and the portable file APIs warn instead of throwing by default.
v6 to v7. The default decorators become TC39 Stage 3 accessors, and the legacy decorators move to envapt/legacy.
v5 to v6. The positional decorator form is removed, and the test-environment behavior changes.
v4 to v5. Renames and behavior shifts to watch when moving off v4.