Make lane count optional and stop displaying it (PP-4506)

[dbernstein]

Description

The Palace Manager backend is removing lane-size maintenance (see ThePalaceProject/circulation#3424), so the admin GET .../lanes response no longer includes a per-lane count.

• interfaces.ts: make LaneData.count optional (count?: number) for backward compatibility with older servers.
• Lane.tsx: stop rendering the " (count)" suffix next to the lane name.

count was display-only — no logic depended on it — so this degrades gracefully and is safe to ship independently of the backend change.

Motivation and Context

JIRA: PP-4506

Companion to ThePalaceProject/circulation#3424, which removes the lane size/count from the backend.

How Has This Been Tested?

• tsc type-check passes.
• tests/jest/components/Lane.test.tsx passes (2/2); Prettier clean.

[claude]

Claude finished @dbernstein's task in 1m 34s —— View job

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Code Review: Make lane count optional and stop displaying it (PP-4506)

• Gather context (read diff, files, and surrounding tests)
• Understand the request (detailed code review)
• Verify no remaining count reads or display assertions
• Post review

Summary

This is a clean, well-scoped change. The display-only " (count)" suffix is removed from Lane.tsx, LaneData.count is made optional with a clear deprecation comment explaining the backward-compat rationale, and the now-obsolete count assertions are dropped from the two affected tests. I confirmed there are no remaining reads of lane.count anywhere in src/ and no surviving (count) display assertions in either the mocha or jest test suites, so the removal is complete and degrades gracefully against both old and new backends. The remaining count: values in the test mock data are harmless (now-optional) and arguably useful for exercising the older-server path, so no change is needed there. No bugs or actionable issues found — looks good to merge.
· feature/PP-4506-lane-count-optional