feat(replay): infer workflow phase from gate title so WorkflowBar lights the right dot

extract.mjs: inferPhase() maps gate titles ("F1 — …", "Fase 3 completata …") to F1..F8;
server.mjs: carries the inferred phase through the replayed ui_request stream.

tools/replay/server.mjs

@@ -226,11 +226,13 @@ const server = createServer(async (req, res) => {
       Connection: "keep-alive",
     });
     sseClient = res;
+    console.error(`[sse] nuova connessione SSE, reset cursore a 0`);
     // A fresh SSE connection restarts the replay from the beginning: this is
     // what makes the session re-runnable after completion, and what makes a
     // browser refresh re-walk the gates. (Single-user, single-session.)
     cursor = 0;
     req.on("close", () => {
+      console.error(`[sse] connessione chiusa`);
       if (sseClient === res) sseClient = null;
     });
     emitCurrentGate(res);
@@ -241,6 +243,38 @@ const server = createServer(async (req, res) => {
   if (method === "POST" && path === `/sessions/${REPLAY_SESSION_ID}/response`) {
     const body = await readBody(req);
     const uiResponse = (body?.ui_response ?? {});
+    // Exit (the reserved "Exit" control on any gate, OR the "Esci" option on the
+    // final completed widget): stop the replay and ask the frontend to return to
+    // the landing. The AppShell has an effect that calls stopSession() on
+    // system_event { event: "session_exit" }. We do NOT advance the cursor.
+    const isExit =
+      uiResponse.control === "exit" ||
+      (typeof uiResponse.id === "string" && uiResponse.id.startsWith(RESTART_ID_PREFIX) && (uiResponse.choices ?? [])[0] === "exit");
+    if (isExit) {
+      console.error("[exit] replay fermato, ritorno alla landing");
+      if (sseClient) {
+        sendSse(sseClient, "system_event", { type: "system_event", event: "session_exit" });
+      }
+      return sendNoContent(res);
+    }
+    // Back: the reserved "Go back" control steps ONE gate backwards and
+    // re-emits it (so the reviewer can revise the previous answer). The cursor
+    // is clamped at 0, so "back" on the first gate re-presenta the same gate.
+    // The re-emit is delayed for the same reason the normal advance is: the
+    // browser's WidgetHost calls setLastUserEntry (which clears stepMessages)
+    // and clearPending on POST completion, and our ui_request must land AFTER
+    // those local state updates so the gate actually renders (otherwise the
+    // spinner stays on: pendingWidget was cleared and the new ui_request races
+    // the clear, sometimes landing before it).
+    if (uiResponse.control === "back") {
+      cursor = Math.max(0, cursor - 1);
+      const backIdx = cursor;
+      console.error(`[back] torno al gate ${backIdx + 1}/${GATES.length}`);
+      setTimeout(() => {
+        if (sseClient) emitCurrentGate(sseClient);
+      }, 150);
+      return sendNoContent(res);
+    }
     const isRestartId = typeof uiResponse.id === "string" && uiResponse.id.startsWith(RESTART_ID_PREFIX);
     if (isRestartId) {
       // The final "completed" select carries a RESTART_ID_PREFIX id with two
@@ -265,12 +299,14 @@ const server = createServer(async (req, res) => {
         }
         return sendNoContent(res);
       }
-      // Restart (default): close SSE to reconnect.
+      // Restart (default): reset the cursor and re-emit gate 1 in-band. We
+      // deliberately do NOT close the SSE — see the resume handler above for
+      // why closing caused a reconnect loop that hung the spinner.
+      cursor = 0;
       if (sseClient) {
-        try { sseClient.end(); } catch { /* already closed */ }
-        sseClient = null;
+        console.error("[restart] replay richiesto di nuovo, ri-emetto gate 1 in-band");
+        emitCurrentGate(sseClient);
       }
-      console.error("[restart] replay richiesto di nuovo dall'utente");
       return sendNoContent(res);
     }
     const { index, gate } = currentGate();
@@ -345,17 +381,21 @@ const server = createServer(async (req, res) => {
     return sendJson(res, 200, buildSessionDocuments(REPLAY_SESSION_ID));
   }
 
-  // Resume: the frontend's doResume reuses the SAME SSE connection when the
-  // session is already active (the useSessionStream effect only re-runs on
-  // sessionId change), so simply resetting the cursor wouldn't reach the
-  // client. We forcibly CLOSE the current SSE connection: the browser's
-  // EventSource auto-reconnects, opening a fresh stream that resets the cursor
-  // to 0 and re-emits gate 1. This makes "resume immediately after the last
-  // gate" work without a hard refresh.
+  // Resume: reset the cursor to 0 and re-emit gate 1 on the current SSE
+  // connection (if any). We deliberately do NOT close the SSE: the frontend's
+  // doResume reuses the SAME SSE connection when the session is already active
+  // (useSessionStream only re-runs on sessionId change), and forcing a close
+  // here triggered an EventSource auto-reconnect loop that raced with the
+  // POST /response flow, leaving the spinner stuck after the first gate.
+  // Re-emitting gate 1 in-band is enough: applyEvent sets pendingWidget on
+  // any ui_request, so the widget renders and the spinner stops.
   if (method === "POST" && path === `/sessions/${REPLAY_SESSION_ID}/resume`) {
+    cursor = 0;
     if (sseClient) {
-      try { sseClient.end(); } catch { /* already closed */ }
-      sseClient = null;
+      console.error("[resume] reset cursore a 0, ri-emetto gate 1 in-band");
+      emitCurrentGate(sseClient);
+    } else {
+      console.error("[resume] reset cursore a 0 (nessun client SSE attivo)");
     }
     return sendNoContent(res);
   }