Pick legacy-inspector-support entry by ember-source version

[NullVoxPopuli-ai-agent]

Summary

Fixes the min-supported try-scenario on #317:

[vite]: Rollup failed to resolve import "@ember/enumerable/mutable"
from ".../@embroider/legacy-inspector-support/src/modules-4-12.js"

@embroider/legacy-inspector-support ships three entry points, each paired with its own modules-*.js tailored to a different ember-source range:

entry	target	notable imports
ember-source-3.28	Ember < 4.8	legacy @ember/-internals/runtime/lib/mixins/mutable_enumerable
ember-source-4.8	Ember >= 4.8 < 4.12	@ember/enumerable/mutable
ember-source-4.12	Ember >= 4.12	@ember/enumerable/mutable + @ember/owner

test-app/app/app.js was hard-coded to ember-source-4.12, so the min-supported scenario (which installs ember-source: ~4.2.0) ended up pulling in modules-4-12.js → @ember/enumerable/mutable, which doesn't exist in Ember 4.2. Rollup couldn't resolve it and the build failed.

Use macroCondition + dependencySatisfies + importSync from @embroider/macros (already a devDependency) to select the entry at build time based on the installed ember-source version:

let setupInspector;
if (macroCondition(dependencySatisfies('ember-source', '>= 4.12.0'))) {
  setupInspector = importSync('@embroider/legacy-inspector-support/ember-source-4.12').default;
} else if (macroCondition(dependencySatisfies('ember-source', '>= 4.8.0'))) {
  setupInspector = importSync('@embroider/legacy-inspector-support/ember-source-4.8').default;
} else {
  setupInspector = importSync('@embroider/legacy-inspector-support/ember-source-3.28').default;
}

The macros compile the untaken branches away, so each try scenario only brings the import graph that its installed ember-source can satisfy.

Test plan

• min-supported (ember-source ~4.2.0) goes green — picks the 3.28 entry
• ember-lts-5.12 / ember-lts-6.4 / ember-latest / ember-beta / ember-alpha still pick the 4.12 entry and remain green
• ember-lts-4.12 picks the 4.12 entry — note: that scenario has a separate, unrelated failure (Rollup failed to resolve import "require" in @ember/test-helpers/-internal/build-registry.js) that this PR does not address

🤖 Generated with Claude Code