feat(response-status): adding agent steps to response status

[aramos-adobe]

Description

Extends swc-response-status to support agentic AI execution states from the ConvAI Response Status design spec, while preserving the existing legacy API (plain-text reasoning + loading / open).

What's included

• swc-response-status-step — light-DOM step descriptor (title, detail, kind, status) slotted into response status
• Agentic mode on swc-response-status when phase is set and/or step children are present:
  • phase: initiating | processing | complete
  • duration for complete summary (Thought for N seconds)
  • initiating-label, loading-label, complete-label
  • Rolling header title from the active step while processing
  • Expandable step timeline (open during processing and complete)
• Animated three-dot loader (replaces swc-progress-circle for loading states in this PR)
• Timeline styling — rail, connector line, thinking/acting detail copy, spacing aligned to Figma
• Storybook updates for response status loading/anatomy copy

Figma reference

Taniya/Aziz working file — Agentic states (node 29-189)

Motivation and context

ConvAI needs a status surface that reflects initiation → processing (collapsed/expanded) → completed (collapsed/expanded) so users can see rolling step titles while the model works and review execution steps after the fact. This PR implements the engineering spike toward that design and unblocks API/RFC review with design.

Addresses parent story SWC-2134 (Support Response Status Design). Related design ticket: SUE-170.

Related issue(s)

• addresses SWC-2134

Screenshots (if appropriate)

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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.

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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

• Agentic states — processing expanded

  1. Open Storybook → Patterns → Conversational AI → Response status
  2. Use markup with phase="processing", open, and multiple swc-response-status-step children
  3. Expect animated three dots, active step title in header, expandable timeline with connectors and thinking/acting detail

• Agentic states — complete collapsed

  1. Set phase="complete" and duration="9" with completed steps
  2. Expect header Thought for 9 seconds, checkmark, chevron when steps exist

• Legacy reasoning (regression)

  1. <swc-response-status loading> then complete with default-slot reasoning text
  2. Expect legacy disclosure behavior unchanged aside from three-dot loader

Device review

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

Accessibility testing checklist

• Keyboard — Tab to disclosure button when steps/reasoning exist; Enter/Space toggles open; focus visible

  1. Storybook → response status with steps and disclosure
  2. Tab to header button, activate
  3. Expect aria-expanded / aria-controls to reflect panel state

• Screen reader — Processing header uses role="status"; step list uses role="list" / listitem

  1. Navigate to agentic processing example
  2. Toggle disclosure
  3. Expect expanded state and step list label (reasoning-label) announced

Known gaps / follow-ups (SWC-2134 sub-tasks)

• Changeset required before merge (changeset-bot)
• Automated tests for agentic paths (SWC-2162)
• duration vs complete-label precedence fix (SWC-2158)
• Design parity sign-off (SWC-2156)
• API RFC and streaming step id pattern (SWC-2157, SWC-2163)

[changeset-bot]

⚠️ No Changeset found

Latest commit: d49cbc7

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[rubencarvalho]

The build is broken here 😄 Please fix so it also deploys

[github-actions]

📚 Branch Preview Links

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Deployed to Azure Blob Storage: pr-6318

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