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/extract.mjs

@@ -139,9 +139,28 @@ if (sessionCounts.size > 1) {
 const answered = calls.filter((c) => resultsByCallId.has(c.callId));
 
 // --- build descriptors (mirrors harness/.pi/extensions/gate/builders.js) ----
+
+// Infer the workflow phase (F1..F8) of a gate from its title, so the frontend's
+// WorkflowBar lights up the correct dot during replay. Patterns (from real
+// session titles):
+//   "F1 — Chiarimento 1/3: …"        → F1
+//   "Fase 3 completata — passo alla  → F3  (the gate that CLOSES phase 3)
+//    Fase 4 (Schema linking)?"
+//   "F6 — CTE 2 approvato: …"        → F6
+// Returns null when no phase can be inferred (the frontend keeps the previous
+// phase in that case, which is fine for transitional gates).
+function inferPhase(title) {
+  if (typeof title !== "string") return null;
+  let m = title.match(/Fase\s+(\d+)\s+completata/i);
+  if (m) return `F${m[1]}`;
+  m = title.match(/\bF([1-8])\b/);
+  if (m) return `F${m[1]}`;
+  return null;
+}
+
 function buildDescriptor(name, args, idx) {
   const id = `u${idx}`;
-  const phase = "replay";
+  const phase = inferPhase(args.title) ?? "replay";
   if (name === "reviewer_select") {
     const opts = parseOptions(args.options).filter((o) => !isReserved(o.label));
     const recommendedId = parseOptions(args.options).find((o) => o.recommended)?.id ?? null;