Refresh the vendored MEOS-API IDL to match upstream

Regenerate vendor/meos-api/meos-idl.json via `make vendor-meos-api` from
MEOS-API@master and the MobilityDB@master headers. The scheduled vendor-drift
check flagged the committed snapshot as stale; this resyncs it (3546 functions,
70 structs, 16 enums, 29 portable bare-name aliases). The regeneration is
deterministic (verified idempotent), so the drift check returns to green.

Author: estebanzimanyi