Follow-ups on the #75382 salvage (review findings):
- _wenv/_get_wsecret now catch UnscopedSecretError and fall back to
os.getenv for the DEFAULT profile's adapter, which constructs and sends
outside any _profile_runtime_scope under multiplexing — a bare
get_secret would crash its WhatsApp path (fixing one profile by
breaking another). Same pattern as Slack SLACK_APP_TOKEN (#59739) and
the Matrix recovery key. Scoped misses still return the default — no
cross-profile borrow.
- bridge_env overlay extended to the full WHATSAPP_* set bridge.js
consumes (DEBUG, FORWARD_OWNER_MESSAGES, REPLY_PREFIX,
MAX_MESSAGE_LENGTH, CHUNK_DELAY_MS, SEND_TIMEOUT_MS).
- Removed the always-true conditional on WHATSAPP_MODE injection.
5438e9c629