fix(action-button): track label content changes after first render

[rubencarvalho]

Description

<swc-action-button>'s default <slot> wasn't bound to SlotTextController's handleSlotChange. hasLabel (and therefore the swc-ActionButton--iconOnly class) was only correct for content present at connect; label text added or removed afterward wasn't tracked.

Motivation and context

SlotTextController requires the observed slot to bind @slotchange for post-first-render changes to be tracked (its MutationObserver only watches characterData, not childList). swc-button, swc-badge, swc-illustrated-message, and swc-card all bind this correctly; swc-action-button was the one outlier, so a consumer app that dynamically clears or sets an action button's label (e.g. a framework re-render) would see the button stay icon-only-styled (or vice versa) with stale spacing until an unrelated property change forced a re-render.

I audited every consumer of SlotTextController (Button.base.ts, Badge.base.ts, IllustratedMessage.base.ts, Card.base.ts) and their concrete render templates; ActionButton.ts was the only one missing the binding. CloseButton overrides hasIcon/hasLabel directly and doesn't use the controller, so it's unaffected.

Related issue(s)

• fixes N/A (found via code review)

Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Dynamic label removal collapses to icon-only

  1. Open Storybook, Action button > Tests > Dynamic label behavior
  2. Run the play function (or manually: render <swc-action-button><svg slot="icon">...</svg>Edit</swc-action-button>, then remove the text node)
  3. Expect the internal <button> to gain swc-ActionButton--iconOnly and tighten its padding

• Dynamic label addition restores label layout

  1. Start from an icon-only action button
  2. Append a text label at runtime
  3. Expect swc-ActionButton--iconOnly to be removed and label spacing to return

Device review

• Did it pass in Desktop?
• Did it pass in (emulated) Mobile?
• Did it pass in (emulated) iPad?

Accessibility testing checklist

• Keyboard (required — document steps below)

  1. No new focusable parts are introduced by this change.
  2. Tab to the action button in the "Dynamic label behavior" story; confirm the focus ring renders identically before and after the label mutation.
  3. Expect no change in tab order or focus behavior.

• Screen reader (required — document steps below)

  1. With VoiceOver/NVDA running, focus the action button in the "Dynamic label behavior" story before the label is removed.
  2. Trigger the label removal (via the play function or devtools), then re-focus or re-announce the button.
  3. Expect the accessible name to still reflect the current accessible-label/visible text combination — the fix only corrects the internal --iconOnly styling class, not aria-label derivation, which was already correct.

[changeset-bot]

🦋 Changeset detected

Latest commit: e37c893

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@adobe/spectrum-wc	Patch

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[github-actions]

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[coveralls]

Coverage Report for CI Build 31117883006

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Coverage: 96.239%

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Coverage Stats

Relevant Lines:	39268
Covered Lines:	37993
Line Coverage:	96.75%
Relevant Branches:	6464
Covered Branches:	6019
Branch Coverage:	93.12%
Branches in Coverage %:	Yes
Coverage Strength:	460.21 hits per line

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