Monitor stazioni: pagina /monitor e proxy JSON (#57)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/frontend/flask_app/blueprints/monitor.py

@@ -0,0 +1,45 @@
+"""Live monitor of the open production runs (#57).
+
+Page at /monitor for admin and Supervisor (capoturno); the page polls a JSON proxy
+of GET /api/production-runs/open every 10 seconds.
+"""
+from functools import wraps
+
+from flask import Blueprint, abort, jsonify, render_template, session
+
+from blueprints.auth import login_required
+from services.api_client import api_client
+
+monitor_bp = Blueprint("monitor", __name__)
+
+
+def monitor_required(f):
+    """Admin or Supervisor only: the same people the backend lets read /open."""
+    @wraps(f)
+    def decorated(*args, **kwargs):
+        user = session.get("user", {})
+        if not (user.get("is_admin") or "Supervisor" in user.get("roles", [])):
+            abort(403)
+        return f(*args, **kwargs)
+    return decorated
+
+
+@monitor_bp.route("", strict_slashes=False)
+@login_required
+@monitor_required
+def index():
+    return render_template("monitor/index.html")
+
+
+@monitor_bp.route("/api/runs")
+@login_required
+@monitor_required
+def api_runs():
+    """JSON proxy polled by the page."""
+    resp = api_client.get("/api/production-runs/open")
+    if isinstance(resp, dict) and resp.get("error"):
+        body = {"error": True, "detail": resp.get("detail", "")}
+        if resp.get("session_expired"):
+            body["session_expired"] = True
+        return jsonify(body), resp.get("status_code", 500)
+    return jsonify(resp)