Deprecate TargetActionSupport, ActionHandler#send, and ActionSupport#send (RFC 1041)

[NullVoxPopuli-ai-agent]

Implements RFC 1041: Deprecate TargetActionSupport.

This finishes the work started in #20969 (the original commit is preserved with @wagenet as author; a follow-up commit replaces the placeholder ids/messages).

What this does

Deprecates the three APIs listed in the RFC's detailed design:

• TargetActionSupport#triggerAction
• ActionHandler#send
• ActionSupport#send (classic component send)

All three emit under a single deprecation id, deprecate-target-action-support, matching the guide added in ember-learn/deprecation-app#1410.

Design decisions (answering the open questions from #20969)

• Deprecation id: deprecate-target-action-support, registered in the DEPRECATIONS object in @ember/-internals/deprecations and emitted via deprecateUntil, like deprecate-comparable-mixin.
• Versions: since: { available: '7.3.0' }, until: '8.0.0'. Per the deprecation-staging convention documented in @ember/-internals/deprecations, enabled is intentionally not set because RFC 1041 is at the Accepted stage, not Ready for Release — so by default the deprecation is staged as available only. (The guide in Add Target Action Support deprecation guide ember-learn/deprecation-app#1410 still says since: 6.8.0 / until: 7.0.0 and will need the same version bump.)
• Route#send is untouched: it has its own implementation and is not in the RFC's list; router-internal event dispatch (triggerEvent) never goes through these mixin methods, so framework internals do not trigger the deprecation.

Tests

Tests exercising the deprecated APIs now use the expectDeprecation(matcher, DEPRECATIONS.DEPRECATE_TARGET_ACTION_SUPPORT.isEnabled) + testUnless(...isRemoved) pattern so they pass in every CI variant. Routing tests that only used send incidentally were migrated off it (e.g. router.refresh() / direct method calls).

Verified locally:

• browser suite in all four variants: default, ALL_DEPRECATIONS_ENABLED=true, OVERRIDE_DEPRECATION_VERSION=15.0.0, and production build — 0 failures
• type-check:internals, type-check:types, eslint, prettier, node tests, and docs coverage

🤖 Generated with Claude Code

[NullVoxPopuli]

It turns out that this PR is actually pretty small -- most of the changes are tests.

Step next: see if our smoke tests throw deprecations (hopefully not?)

@kategengler or @mansona do we have a way to run the tutorial ci against an ember.js PR?

(if not, this would be immensely helpful for the slew of deprecations we need to ship in v7)

[kategengler]

Just took a quick look since it is past my bedtime.

I think this is broader than TargetActionSupport which is fine since I think most of it is vestigial, but we should update the RFC.

I think the deprecation messages could use some work.

I'm suspicious of the tests in some of test files that do not have expectDeprecation -- should including the mixin also throw a deprecation ala the deprecation for the Comparable mixin?

ember.js/packages/@ember/-internals/runtime/lib/mixins/comparable.ts

Lines 41 to 47 in ce5b156

	init() {
	this._super(...arguments);
	deprecateUntil(
	'The `Comparable` mixin is deprecated. Implement a `compare` method directly on your class instead.',
	DEPRECATIONS.DEPRECATE_COMPARABLE_MIXIN
	);
	},