Custom RTMP saved accounts, CUSTOM destination prepare, debug logging

- Add POST /providers/accounts/custom-rtmp endpoint for saved RTMP servers
- Encrypt rtmpUrl/streamKey in accessTokenEnc/refreshTokenEnc fields
- Decrypt and return rtmpUrl/streamKey in GET /providers/accounts for CUSTOM_RTMP
- Skip token revocation on DELETE for CUSTOM_RTMP accounts
- Decrypt CUSTOM_RTMP credentials into CUSTOM destinations on plan create/update
- Handle CUSTOM destinations in prepare lifecycle (already READY, skip provider auth)
- Add debug logging for plan operations and user upsert

src/types/api.ts

@@ -39,6 +39,14 @@ export interface LinkedAccountResponse {
   displayName: string;
   accountId: string;
   avatarUrl: string | null;
+  rtmpUrl?: string;
+  streamKey?: string;
+}
+
+export interface CreateCustomRtmpBody {
+  displayName: string;
+  rtmpUrl: string;
+  streamKey: string;
 }
 
 // ── Streams ──────────────────────────────────────────────
@@ -63,6 +71,8 @@ export interface CreateDestinationBody {
   privacyStatus?: string;
   gameId?: string;
   tags?: string;
+  rtmpUrl?: string;
+  streamKey?: string;
 }
 
 export interface StreamPlanResponse {