fix(mcp-server): social-fast-coordinator-pipeline — stage_transition used non-existent currentStage field

FastingSessionDoc has stages: unknown[] not currentStage: string.
- Replace currentStage cast with hasStages check (session.stages.length > 0)
- Fix protocolId extraction to use direct field (session?.protocolId)
- Report currentStage derived from stages.length as 'stage_N' indicator

services/mcp-server/src/modules/a2a/social-fast-coordinator-pipeline.ts

@@ -83,9 +83,10 @@ async function notifyMembers(
       });
     }
 
-    // If session has a current stage, fire stage_transition milestone push
-    const stage = (session as unknown as Record<string, unknown>)?.['currentStage'];
-    if (stage && typeof stage === 'string') {
+    // If session has stage entries (fast is progressing), fire stage_transition milestone push
+    const hasStages =
+      session !== null && Array.isArray(session.stages) && session.stages.length > 0;
+    if (hasStages) {
       try {
         await nomgapPushFire({ type: 'stage_transition', userId }, opts);
         results.push({ userId, type: 'stage_transition', outcome: 'fired' });
@@ -128,9 +129,10 @@ async function sendWeeklyDigestAndReport(
   const fired = notifications.filter(n => n.outcome === 'fired').length;
   const failed = notifications.filter(n => n.outcome === 'failed').length;
   const stage =
-    ((session as unknown as Record<string, unknown>)?.['currentStage'] as string | null) ?? null;
-  const protocolId =
-    ((session as unknown as Record<string, unknown>)?.['protocolId'] as string | null) ?? null;
+    session && Array.isArray(session.stages) && session.stages.length > 0
+      ? `stage_${session.stages.length}`
+      : null;
+  const protocolId = session?.protocolId ?? null;
 
   const summary =
     memberUserIds.length === 0