feat(backend): spawnFor new/resume prompt mode; resume sends /riprendi-sessione

backend/src/pi/pi-process-manager.ts

@@ -47,7 +47,7 @@ export class PiProcessManager {
 
   async spawnFor(
     sessionId: string,
-    o: { provider?: string; model?: string; thinking?: string; author?: string },
+    o: { provider?: string; model?: string; thinking?: string; author?: string; mode?: "new" | "resume" },
   ): Promise<SessionRuntime> {
     // Idempotent per session id: tear down any existing runtime for this id
     // first (before the cap check) so a resume/respawn neither leaks the old
@@ -80,7 +80,10 @@ export class PiProcessManager {
       await rpc.request({ type: "set_thinking_level", level: thinking } as object & { type: string });
     }
 
-    rpc.send({ type: "prompt", message: `/nuova-domanda "kickoff"` });
+    const message = o.mode === "resume"
+      ? `/riprendi-sessione ${sessionId}`
+      : `/nuova-domanda "kickoff"`;
+    rpc.send({ type: "prompt", message });
     return rt;
   }
 
@@ -90,6 +93,7 @@ export class PiProcessManager {
       provider: manifest?.provider,
       model: manifest?.model,
       thinking: manifest?.thinking,
+      mode: "resume",
     });
   }