fix: Close window when unfocused

lua/javelin/ui.lua

···
 				open_buf(file)
 			end,
 		},
+		on_buf = function(self)
+			vim.api.nvim_create_autocmd("BufLeave", {
+				buffer = self.buf,
+				callback = function()
+					if not self.closed then
+						self:close()
+					end
+					return true
+				end,
+			})
+		end,
 		on_close = function(self)
 			if self.buf then
 				local lines = self:lines()