Add integration and drift-detection tests

[imnasnainaec]

Current tests cover parsers, components, hooks, and utils well (~45 files), but there is no test that goes USJ input → extractBookFromUsj → tokenizeBook → rendered segments with analyses joined, and no test of what happens to existing links when the baseline changes (hash change, token shift, stale flipping). Add:

• One integration test with a small real USJ fixture, a seeded TextAnalysis, and assertions on rendered glosses/phrases.
• Drift tests: same fixture with an edited verse — assert snapshot mismatch detection and (once Decide the token/segment identity re-anchoring strategy #136 lands) re-anchoring behavior.
• A cross-segment phrase edge-case test (model permits it; UI disables it — pin the current behavior).

Size: S–M