fix(FN-703): fix overly broad usage limit pattern and add transient error retry

- Narrow 'insufficient' usage-limit regex to require quota/credit/balance/fund context
- Add transient error detection in executor and triage to retry instead of failing
- Improve scheduler pause/resume logging with actionable messages and resume confirmation
- Add SSE active connection counter for observability
- Add duplicate usage-limit pause suppression logging

packages/engine/src/scheduler.ts

@@ -331,21 +331,27 @@ export class Scheduler {
       // Global pause (hard stop): halt all scheduling activity
       if (settings.globalPause) {
         if (!this.wasGlobalPaused) {
-          schedulerLog.log("Global pause active — scheduling halted");
+          schedulerLog.warn("⚠ Global pause active — scheduling halted. To resume: set globalPause to false in settings.");
           this.wasGlobalPaused = true;
         }
         return;
       }
+      if (this.wasGlobalPaused) {
+        schedulerLog.log("Global pause cleared — scheduling resumed");
+      }
       this.wasGlobalPaused = false;
 
       // Engine paused (soft pause): halt new work dispatch, but let agents finish
       if (settings.enginePaused) {
         if (!this.wasEnginePaused) {
-          schedulerLog.log("Engine paused — scheduling halted (in-flight agents continue)");
+          schedulerLog.warn("⚠ Engine paused — scheduling halted (in-flight agents continue). To resume: set enginePaused to false.");
           this.wasEnginePaused = true;
         }
         return;
       }
+      if (this.wasEnginePaused) {
+        schedulerLog.log("Engine pause cleared — scheduling resumed");
+      }
       this.wasEnginePaused = false;
 
       // Count only in-progress tasks toward the worktree limit.