🤖 tests: characterize consumer breakdown cache hydration in WorkspaceStore

[ThomasK33]

Summary

Adds characterization tests for the Costs tab consumer breakdown in WorkspaceStore: when the store shows the token-stats cache persisted in session-usage.json, and when it recounts instead. Test-only change, no production code changes.

Background

This PR is part of the CRAP code-quality campaign. No test called getWorkspaceConsumers (CC 8, CRAP 72) or getMaxHistorySequence (CC 6, CRAP 42) in src/browser/stores/WorkspaceStore.ts. With these tests, merged CI coverage plus a local run scores both at 100% coverage (CRAP 8 and 6).

Implementation

Each test loads a session usage with a tokenStatsCache, then replays a two-message history (sequences 3 and 7) and reads getWorkspaceConsumers. The chat script holds the replay until the session usage is in memory, so catch-up sees the cache. The tests cover:

• a matching cache (count, newest sequence, model, provider fingerprint) is shown as is, with no recount;
• a different newest history sequence or message count starts a recount;
• a cache without maxHistorySequence falls back to the message count;
• after a provider config change drops the cache, the next getWorkspaceConsumers read schedules the recount.

Validation

• Mutants (newest sequence computed as the minimum, newest sequence always unknown, the sequence check or the count check dropped, the lazy trigger in getWorkspaceConsumers removed): each fails at least one new test.
• One mutant survives: dropping the caughtUp condition in getWorkspaceConsumers. Before catch-up the aggregator holds no messages in these flows, so the condition changes nothing a test can see here. I did not add a test for it.

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Generated with xum • Model: anthropic:claude-opus-5-5 • Thinking: high

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-13T08:36:29.933860Z	dc3cfae	PR opened
🔒 Security Review	✅ Completed 2026-10-13T08:39:59.510714Z	dc3cfae	PR opened

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