[PLAN] AI Credits onboarding: Download AntSeed step content

[blueogin]

[PLAN] AI Credits onboarding: Download AntSeed step content

Parent issue: #177

Scope: This sub-issue covers section 4. Download AntSeed from #177.

Builds on: #183 for the Setup tab foundation.

Relevant design references

Use these parent-issue screenshots as the primary visual references for this slice.

Download AntSeed step

This clarifies that Download AntSeed is the first Setup step and that it should surface the AntSeed VPR/Desktop download action.

Overall onboarding flow context

Use this to preserve the intended placement of Download AntSeed within the full Setup experience.

Required states, flows, and behaviors

• Add Download AntSeed as the first actionable step in Setup.
• Surface the AntSeed VPR/Desktop download link from this step.
• Keep the step ordering aligned with [Feature] AI Credits: Update Setup onboarding, signer key flow, and AntSeed guidance #177: Download AntSeed → Signer Key → Authorize Wallet.
• Present this as onboarding content inside Setup without changing the existing Buy deposit/stream flow.
• Existing Buy, Manage, and History behavior must remain unchanged.

Execution plan

• Extend the Setup step structure introduced in packages/ai-credits-widget/src/components/flow/ under [PLAN] AI Credits onboarding: inline wallet connection and Setup tab foundation #183 so Download AntSeed is the first step.
• Add widget-local UI for the Download AntSeed step content under packages/ai-credits-widget/src/components/ using existing @goodwidget/ui primitives.
• Wire the AntSeed download action as an external link and keep the stepper/state presentation consistent with the rest of Setup.
• Update Storybook QA fixtures/docs to show the Download AntSeed state in Setup.
• Update Playwright smoke coverage to verify the Download AntSeed step is present and linked correctly.

Acceptance criteria

• Download AntSeed is the first step in Setup.
• The step links users to AntSeed VPR/Desktop.
• Step order is Download AntSeed → Signer Key → Authorize Wallet.
• Existing Buy deposit/stream flow remains separate and unchanged.
• Existing Manage and History flows remain unchanged.
• Storybook fixtures/docs cover the Download AntSeed step.
• Playwright smoke tests cover the Download AntSeed step and link behavior.

Human-reviewer checklist

• Confirm this slice covers only the Download AntSeed requirement from [Feature] AI Credits: Update Setup onboarding, signer key flow, and AntSeed guidance #177.
• Confirm Download AntSeed appears first in Setup.
• Confirm the outbound download link is correct.
• Confirm the existing Buy flow was not moved into Setup.
• Confirm Storybook and Playwright coverage were updated for this step.