fix(agent): prevent session lock deadlock on timeout during compaction (#9855)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 64a28900f1
Co-authored-by: mverrilli <816450+mverrilli@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/agents/pi-embedded-runner/run.overflow-compaction.e2e.test.ts

@@ -206,6 +206,7 @@ function makeAttemptResult(
   return {
     aborted: false,
     timedOut: false,
+    timedOutDuringCompaction: false,
     promptError: null,
     sessionIdUsed: "test-session",
     assistantTexts: ["Hello!"],