fix(catalogue): apoc.convert.fromJsonMap throws query-wide on malformed range value

[JanSmrcka]

Context

In `services/catalogue-service/catalogue-db-queries.go` the range-typed property logic uses:

```cypher
apoc.convert.fromJsonMap(pv.value)
```

Two locations:

• Line ~146: range filter (existing)
• Line ~270 (sort path added in PR fix(catalogue): items sort whitelist + custom property UID #416): `toFloat(apoc.convert.fromJsonMap(pvSort0.value).min)`

`apoc.convert.fromJsonMap` on a malformed string throws a Cypher-level exception — the whole query 500s, not just the one row.

Why this matters now

PR #416 made range-typed properties sortable, which means a single bad-data row in any item that has a range custom property → entire list endpoint dies whenever someone sorts by that column.

Mitigation options

1. Defensive parse: switch to a lenient JSON helper or wrap in `apoc.do.when` with a fallback to null.
2. Type-coerce-and-skip: `CASE WHEN pv.value STARTS WITH '{' THEN apoc.convert.fromJsonMap(pv.value).min ELSE null END` — handles the most common bad-data case (empty string).
3. Backfill: data audit + normalize all range values to valid JSON.

Option 2 is the cheapest defensive fix.

Acceptance

• Inject a row with `pv.value = 'bogus'` for a range property; the sort + filter queries still return 200.
• Item appears at the head/tail (null sort) instead of crashing the response.