feat: add agentcore banner to CLI

[nborges-aws]

Description

Add banner to start page of agentcore CLI. Also includes version badge. Currently set to "AgentCore CLI" and "v1.0.0"

Changes:

• adds banner component, rendering banner and badge
• updates Layout to include banner on home screen
• badge component for rendering version
• small GradientText component to handle gradient styling of banner
• tests exerting banner shows on correct page & gradient behavior

Example

{video incoming}

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the
terms of your choice.

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[agentcore-devx-automation]

AgentCore Harness Review

Verdict: Looks good

Nice, self-contained addition. I read through BrandBanner, Layout, RouterScreen, Badge, and GradientText and didn't find anything that needs to change before merge.

A few small observations that are not blockers — mentioning only in case they're useful:

• src/components/ui/badge/Badge.tsx: the borderStyle mixes rounded (╭, ╯) with square (┐, └) corners. If that mismatch is intentional, ignore; if not, you probably want all four corners to be the same style (e.g. all rounded via borderStyles.rounded from _core.ts).
• src/components/ui/badge/Badge.tsx: label is only .toUpperCase()'d when children is a plain string. <Badge>v{PACKAGE_VERSION}</Badge> passes an array of JSX children and stays lowercase, while <Badge>{v${PACKAGE_VERSION}}</Badge> would get uppercased. The current test happens to exercise the first form, but this is a subtle footgun for future callers.
• src/components/ui/gradient-text/GradientText.tsx: interpolateGradientColor doesn't clamp position to [0, 1]. Current callers stay in-range (index / max(1, span-1) with index < span), so it's fine today; worth clamping if this becomes a shared utility.
• No telemetry is added, which seems appropriate here since this is a purely decorative banner with no new user action to instrument.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.05%. Comparing base (92b6a43) to head (f932da9).

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2223   +/-   ##
=========================================
  Coverage     97.05%   97.05%           
=========================================
  Files           555      560    +5     
  Lines         38385    38480   +95     
=========================================
+ Hits          37253    37348   +95     
  Misses         1132     1132           

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