…nyuan99)

* fix(voice-call): validate provider credentials from env vars

The `validateProviderConfig()` function now checks both config values
AND environment variables when validating provider credentials. This
aligns the validation behavior with `resolveProvider()` which already
falls back to env vars.

Previously, users who set credentials via environment variables would
get validation errors even though the credentials would be found at
runtime. The error messages correctly suggested env vars as an
alternative, but the validation didn't actually check them.

Affects all three supported providers: Twilio, Telnyx, and Plivo.

Fixes #1709

Co-Authored-By: Claude <[email protected]>

* Add per-sender group tool policies

* fix(msteams): correct typing indicator sendActivity call

* fix: require gateway auth by default

* docs: harden VPS install defaults

* security: add mDNS discovery config to reduce information disclosure (#1882)

* security: add mDNS discovery config to reduce information disclosure

mDNS broadcasts can expose sensitive operational details like filesystem
paths (cliPath) and SSH availability (sshPort) to anyone on the local
network. This information aids reconnaissance and should be minimized
for gateways exposed beyond trusted networks.

Changes:
- Add discovery.mdns.enabled config option to disable mDNS entirely
- Add discovery.mdns.minimal option to omit cliPath/sshPort from TXT records
- Update security docs with operational security guidance

Minimal mode still broadcasts enough for device discovery (role, gatewayPort,
transport) while omitting details that help map the host environment.
Apps that need CLI path can fetch it via the authenticated WebSocket.

* fix: default mDNS discovery mode to minimal (#1882) (thanks @orlyjamie)

---------

Co-authored-by: theonejvo <[email protected]>
Co-authored-by: Peter Steinberger <[email protected]>

* fix(security): prevent prompt injection via external hooks (gmail, we… (