Rewind chat or files from any user message (#1154)

* Add Pi extension-launch plumbing for in-process tree primitives

* Add Rewind controls for agent sessions

* Preserve SDK checkpoint env var so Claude file rewind works

The SDK injects CLAUDE_CODE_ENABLE_SDK_FILE_CHECKPOINTING=true when file checkpointing is enabled. The earlier parent-env stripping from c4782ec71c was too broad and removed that child flag along with real parent-session markers.

Keep stripping parent markers, but preserve the checkpoint flag so the SDK rewind path can run directly. With that boundary fixed, the JSONL file-rewind fallback is no longer needed.

* Update OpenCode history replay tests for rewind state

* Show Rewind actions in an adaptive sheet

* Fix rewind semantics across providers

* Refactor Pi IDs through extension capture

* Restore user message to composer after rewind

* Fix Claude rewind tool result mapping

* Fix Claude rewind session switch roundtrip

* Fix rewind and optimistic message regressions

* Tighten rewind test discipline

* Fix OpenCode optimistic message reconciliation

* Reconcile optimistic user messages by marker

* Reorder user message actions

* Unify provider user message contract

* Add Claude rewind flow Playwright contract

* Add Codex rewind flow Playwright contract

* Add OpenCode rewind flow Playwright contract

* Add Pi rewind flow Playwright contract

* Remove real-provider rewind Playwright contracts

* Gate real-provider rewind specs from CI Playwright

packages/server/src/client/daemon-client.ts

@@ -64,6 +64,7 @@ import type {
   ProviderDiagnosticResponseMessage,
   DaemonGetStatusResponse,
   DaemonGetPairingOfferResponse,
+  AgentRewindResponseMessage,
   ListTerminalsResponse,
   CreateTerminalResponse,
   SubscribeTerminalResponse,
@@ -2232,6 +2233,40 @@ export class DaemonClient {
     await this.sendAgentMessage(agentId, text, options);
   }
 
+  async rewindAgent(
+    agentId: string,
+    messageId: string,
+    mode: "conversation" | "files" | "both",
+  ): Promise<AgentRewindResponseMessage["payload"]> {
+    const requestId = this.createRequestId();
+    const message = SessionInboundMessageSchema.parse({
+      type: "agent.rewind.request",
+      requestId,
+      agentId,
+      messageId,
+      mode,
+    });
+    const payload = await this.sendRequest({
+      requestId,
+      message,
+      timeout: 15000,
+      options: { skipQueue: true },
+      select: (msg) => {
+        if (msg.type !== "agent.rewind.response") {
+          return null;
+        }
+        if (msg.payload.requestId !== requestId) {
+          return null;
+        }
+        return msg.payload;
+      },
+    });
+    if (!payload.ok) {
+      throw new Error(payload.error ?? "Agent rewind failed");
+    }
+    return payload;
+  }
+
   async cancelAgent(agentId: string): Promise<void> {
     const requestId = this.createRequestId();
     const message = SessionInboundMessageSchema.parse({