Portofolio auto-sync: otomatis update saat transaksi berubah + tombol Rekalkulasi

- saat.transaksi.create/write/unlink memicu rekalkulasi portofolio otomatis
  (buka menu Portofolio selalu data segar, tanpa klik manual)
- Tambah tombol 'Rekalkulasi' di form portofolio sbg cadangan (action_recalc_click)
- Perbaiki help teks portofolio yg sebelumnya menyesatkan

addons/saat_invest/models/portofolio.py

@@ -75,6 +75,19 @@ class SaatPortofolio(models.Model):
             'count': len(portfolios),
         }
 
+    def action_recalc_click(self):
+        """Tombol 'Rekalkulasi' untuk UI web: hitung ulang lalu muat ulang view list."""
+        result = self.env['saat.portofolio'].action_recalculate()
+        # kembalikan action window portofolio agar view ter-refresh
+        action = {
+            'type': 'ir.actions.act_window',
+            'name': 'Portofolio',
+            'res_model': 'saat.portofolio',
+            'view_mode': 'list,form',
+            'target': 'current',
+        }
+        return action
+
     # --- computed store fields ---
     @api.depends('total_beli_lembar', 'total_jual_lembar')
     def _compute_sisa(self):