fix(search): resolve null entrances in cave search results

[ClemRz]

🤔 What

• Fix entrances field in cave search results returning [null, null, ...] instead of actual entrance IDs
• Add regression tests for toSimpleCave entrance ID extraction

🤷‍♂️ Why

The quick-search endpoint (POST /api/v1/search) returns null values in the entrances array for cave results. This happens because the production Typesense index stores entrance IDs as plain integers (e.g., [20, 21, 25877]), but the toSimpleCave converter assumed they would always be Waterline objects with an .id property. Calling .id on a number yields undefined, which JSON serializes as null.

🔍 How

Changed source.entrances?.map((e) => e.id) to source.entrances?.map((e) => e?.id ?? e) in toSimpleCave. This handles both formats:

• Waterline objects (from DB queries with .populate()) → extracts .id
• Plain IDs (from Typesense indexed documents) → passes through as-is

🧪 Testing

npm run test -- --grep "toSimpleCave"

Four new test cases cover:

1. Waterline objects → extracts IDs
2. Plain numeric IDs (Typesense format) → passes through
3. String IDs → passes through
4. Absent entrances field → returns undefined

[Paul-AUB]

Suggestions (Should Consider)

1. [test/integration/1_services/Converters.test.js] The null-in-array edge case is not covered. With e?.id ?? e, a null entry evaluates as null?.id → undefined, then undefined ?? null → null, so nulls pass through silently. This matches the old broken behavior and could mask corrupt Typesense documents. Consider adding a test that documents the current behavior (or asserts that nulls are filtered out, if that's the desired outcome).

Nitpicks (Optional)

2. [test/integration/1_services/Converters.test.js] Consider adding a test for entrances: [] (empty array). It's trivially handled by the current code, but it documents the contract and prevents future regressions if anyone refactors the optional-chaining logic.

[ClemRz]

Both review items addressed in 6c950a2:

1. Null-in-array edge case — Added .filter((e) => e != null) after the .map() in toSimpleCave so null/undefined entries from corrupt Typesense documents are stripped rather than passing through silently. Added a regression test.

2. Empty array contract test — Added a test for entrances: [] documenting it returns [].

All 3107 tests pass, lint clean.