Add shared breadcrumb component

[jmarrxyz]

Summary

Adds a shared Breadcrumb component for hierarchical navigation across ProtoFleet detail surfaces. The component supports linked ancestor segments plus an optional current-segment sibling switcher, which lets follow-up detail pages replace one-off back buttons with consistent location context.

How it works

Callers pass an ordered segments array. Non-current segments with to render as React Router links, while the current segment renders as text or as a button-backed switcher when siblings are supplied. The switcher handles click-away dismissal, Escape dismissal, keyboard navigation, and selection through useNavigate.

Diagrams

flowchart LR
  caller["Detail page or story"] --> breadcrumb["Breadcrumb"]
  breadcrumb --> ancestors["Ancestor links"]
  breadcrumb --> current["Current segment"]
  current --> switcher["Optional sibling switcher"]
  switcher --> navigate["React Router navigate"]

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Areas of the code involved

Area / file	What changed	Why it matters for review
client/src/shared/components/Breadcrumb/	New component, index export, and Storybook stories	Reusable navigation primitive used by the follow-up detail-view PRs

Key technical decisions & trade-offs

Decision	Trade-off
Keep the component data-driven via segments	Callers own fetching labels/siblings, keeping the shared component UI-only
Allow only the current segment to expose siblings	Keeps keyboard and menu behavior narrow and predictable

Testing & validation

• Storybook checked locally for site, building, and rack breadcrumb shapes.
• Targeted ESLint passed for the component files.
• Full client-typecheck is currently blocked by unrelated infra/maintenance TypeScript errors already present on the parent branch.

[github-actions]

🔐 Codex Security Review

Note: This is an automated security-focused code review generated by Codex.
It should be used as a supplementary check alongside human review.
False positives are possible - use your judgment.

Scope summary

• Reviewed pull request diff only (5bba3f7d0cf10dc2ce406bd484f8a8a89de22147...12d782e995a542fa5d91fd6a628e9eee571392c6, exact PR three-dot diff)
• Model: gpt-5.5

💡 Click "edited" above to see previous reviews for this PR.

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Review Summary

Overall Risk: NONE

Findings

No security, correctness, or reliability findings in the reviewed diff.

Notes

Reviewed .git/codex-review.diff only. The PR adds a shared React breadcrumb component, Storybook stories, and an index export. I did not find changed backend, protobuf, plugin, discovery, database, Docker, or pool-configuration behavior in scope.

Labels are rendered as React text, not HTML, and the added stories use static internal routes. Static diff checks passed with git diff --check.

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_{Generated by Codex Security Review |
Triggered by: @jmarrxyz |
Review workflow run}

[flesher]

looks good, but you need to fix up CI failures before merging