feat(gateway): expose context usage and warning events

src/gateway/session-bridge.ts

@@ -200,6 +200,47 @@ export class SessionBridge {
     return results;
   }
 
+  /** Get estimated context budget for all active sessions. */
+  getAllContextUsage(): Array<{
+    sessionId: string;
+    budget: {
+      estimatedTokens: number;
+      contextWindow: number;
+      remainingTokens: number;
+      usagePct: number;
+      thresholdPct: number;
+      thresholdTokens: number;
+      shouldCompact: boolean;
+    };
+  }> {
+    const results: Array<{
+      sessionId: string;
+      budget: {
+        estimatedTokens: number;
+        contextWindow: number;
+        remainingTokens: number;
+        usagePct: number;
+        thresholdPct: number;
+        thresholdTokens: number;
+        shouldCompact: boolean;
+      };
+    }> = [];
+
+    const seen = new Set<string>();
+    for (const client of this.clients.values()) {
+      if (seen.has(client.sessionId)) {
+        continue;
+      }
+      seen.add(client.sessionId);
+      results.push({
+        sessionId: client.sessionId,
+        budget: client.agent.getContextBudget(),
+      });
+    }
+
+    return results;
+  }
+
   private getOrCreateAgent(sessionId: string): AgentOrchestrator {
     let agent = this.agents.get(sessionId);
     if (!agent) {
@@ -233,6 +274,14 @@ export class SessionBridge {
           keepTurns: config.compaction.keep_turns,
           summaryMaxTokens: config.compaction.summary_max_tokens,
           importanceThreshold: config.compaction.importance_threshold,
+          proactive: {
+            enabled: config.compaction.proactive.enabled,
+            warnPct: config.compaction.proactive.warn_pct,
+            checkpointPct: config.compaction.proactive.checkpoint_pct,
+            autoCompactPct: config.compaction.proactive.auto_compact_pct,
+            checkpointCooldownMs: config.compaction.proactive.checkpoint_cooldown_ms,
+            memoryNamespace: config.compaction.proactive.memory_namespace,
+          },
         } : undefined,
         modelName: config?.models.default.model,
         contextWindow: config?.models.default.context_window,