fix: allow agent workspace directories in media local roots (#17136)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 7545ef1e19
Co-authored-by: MisterGuy420 <255743668+MisterGuy420@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/gateway/server-methods/send.ts

@@ -199,6 +199,9 @@ export const sendHandlers: GatewayRequestHandlers = {
           to: resolved.to,
           accountId,
           payloads: [{ text: message, mediaUrl, mediaUrls }],
+          agentId: providedSessionKey
+            ? resolveSessionAgentId({ sessionKey: providedSessionKey, config: cfg })
+            : derivedAgentId,
           gifPlayback: request.gifPlayback,
           deps: outboundDeps,
           mirror: providedSessionKey