Follow-up on the two salvaged commits:
- One _sidecar_payload_text() helper decides the /send text for both the adapter
path and _standalone_send (cron / send_message), which had the same raw-markdown
leak on URL-bearing messages and never stripped with PHOTON_MARKDOWN=false.
- BlueBubbles (same iMessage surface) keeps [label](url) targets as bare URLs.
- Tests trimmed to two invariants.