[codex] Remove Codex SDK canary runtime (#220)

* Revert "fix: drain sdk follow-up turns (#219)"

This reverts commit 807828e0ce.

* Revert "feat: feature-flag Codex SDK runner (#218)"

This reverts commit 879d16235f.

src/group-queue-state.ts

@@ -37,7 +37,6 @@ export interface GroupState {
   pendingTasks: QueuedTask[];
   process: ChildProcess | null;
   processName: string | null;
-  drainFollowUpsAfterRun: boolean;
   ipcDir: string | null;
   retryCount: number;
   retryTimer: ReturnType<typeof setTimeout> | null;
@@ -61,7 +60,6 @@ export function createGroupState(): GroupState {
     pendingTasks: [],
     process: null,
     processName: null,
-    drainFollowUpsAfterRun: false,
     ipcDir: null,
     retryCount: 0,
     retryTimer: null,
@@ -147,7 +145,6 @@ export function resetRunState(state: GroupState, groupJid: string): void {
   state.startedAt = null;
   state.process = null;
   state.processName = null;
-  state.drainFollowUpsAfterRun = false;
   state.ipcDir = null;
   state.directTerminalDeliveries.clear();
   transitionRunPhase(state, groupJid, 'idle');
@@ -163,8 +160,7 @@ export function assertRunPhaseInvariants(
         state.currentRunId != null ||
         state.runningTaskId != null ||
         state.process != null ||
-        state.processName != null ||
-        state.drainFollowUpsAfterRun
+        state.processName != null
       ) {
         logger.error(
           {
@@ -174,7 +170,6 @@ export function assertRunPhaseInvariants(
             runningTaskId: state.runningTaskId,
             hasProcess: state.process != null,
             processName: state.processName,
-            drainFollowUpsAfterRun: state.drainFollowUpsAfterRun,
           },
           'Invariant violation: idle phase has stale run/task ID or process',
         );