fix: OnlyOffice edit session token expiration and add session expired modal

backend/handlers/auth.go

@@ -210,6 +210,27 @@ func (h *AuthHandler) GetDownloadToken(c *fiber.Ctx) error {
 	})
 }
 
+// GetEditToken issues a 24-hour token for file editing via OnlyOffice
+// GET /api/auth/edit-token
+func (h *AuthHandler) GetEditToken(c *fiber.Ctx) error {
+	userID := c.Locals("userID")
+	username := c.Locals("username")
+
+	token, err := middleware.GenerateEditToken(
+		int(userID.(float64)),
+		username.(string),
+		h.Config.JWTSecret,
+		"",
+	)
+	if err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to generate edit token"})
+	}
+
+	return c.JSON(fiber.Map{
+		"token": token,
+	})
+}
+
 // Enable2FA generates a TOTP secret and returns the provisioning URI.
 // POST /api/auth/2fa/enable
 func (h *AuthHandler) Enable2FA(c *fiber.Ctx) error {