refactor(agents): replace console.warn with SubsystemLogger in compaction-safeguard.ts (#9974)

Merged via squash.

Prepared head SHA: 35dcc5ba35
Co-authored-by: dinakars777 <250428393+dinakars777@users.noreply.github.com>
Co-authored-by: jalehman <550978+jalehman@users.noreply.github.com>
Reviewed-by: @jalehman

src/agents/pi-extensions/compaction-safeguard.ts

@@ -726,7 +726,7 @@ export default function compactionSafeguardExtension(api: ExtensionAPI): void {
       // Use a WeakSet to track which session managers have already logged the warning.
       if (!ctx.model && !runtime?.model && !missedModelWarningSessions.has(ctx.sessionManager)) {
         missedModelWarningSessions.add(ctx.sessionManager);
-        console.warn(
+        log.warn(
           "[compaction-safeguard] Both ctx.model and runtime.model are undefined. " +
             "Compaction summarization will not run. This indicates extensionRunner.initialize() " +
             "was not called and model was not passed through runtime registry.",
@@ -737,7 +737,7 @@ export default function compactionSafeguardExtension(api: ExtensionAPI): void {
 
     const apiKey = await ctx.modelRegistry.getApiKey(model);
     if (!apiKey) {
-      console.warn(
+      log.warn(
         "Compaction safeguard: no API key available; cancelling compaction to preserve history.",
       );
       return { cancel: true };