Replace the single healthcheck_profile with a healthcheck_profiles list so a
host can run several checks (e.g. hk2: pdns, rustdesk, hk2aux). Profiles emit
per-check JSON to latest-<check>.json; the dispatcher clears stale per-check
files, runs every profile, and merges them into latest.json.
Contract: a single complete check keeps the historical verbatim latest.json
shape; several checks produce a worst-status aggregate retaining every check's
detail. A profile that crashes before reporting is aggregated as unknown so
latest.json can never go stale while the dispatcher fails. The dispatcher exits
with the worst (max) profile exit code.
windyboy