refactor: split script into modules and drop queue save/load

tests/history_client_spec.lua

@@ -0,0 +1,60 @@
+local function assert_equal(actual, expected, message)
+	if actual ~= expected then
+		error(
+			(message or "values differ")
+				.. string.format("\nexpected: %s\nactual: %s", tostring(expected), tostring(actual))
+		)
+	end
+end
+
+local function assert_nil(value, message)
+	if value ~= nil then
+		error((message or "expected nil") .. string.format("\nactual: %s", tostring(value)))
+	end
+end
+
+local function assert_truthy(value, message)
+	if not value then
+		error(message or "expected truthy value")
+	end
+end
+
+package.loaded["history_client"] = nil
+package.loaded["json"] = nil
+
+local calls = {}
+local notices = {}
+local client = require("history_client").new({
+	mp = {
+		command_native_async = function(command, callback)
+			table.insert(calls, command)
+			callback(true, { status = 0 }, nil)
+		end,
+	},
+	options = {
+		use_history_db = true,
+		backend_host = "http://backend.test",
+		backend_port = "42069",
+	},
+	notify = function(message)
+		table.insert(notices, message)
+	end,
+})
+
+assert_nil(client.save_queue, "queue save backend API should be removed")
+assert_nil(client.load_queue, "queue load backend API should be removed")
+
+local ok = client:add_video({
+	video_name = "Demo",
+	video_url = "https://example.test/watch?v=1",
+})
+
+assert_truthy(ok, "add_video should still be enabled for shared backend")
+assert_equal(#calls, 1, "add_video should issue one backend request")
+assert_equal(calls[1].args[1], "curl", "backend request should use curl subprocess")
+assert_equal(
+	calls[1].args[4],
+	"http://backend.test:42069/add_video",
+	"backend request should target add_video endpoint"
+)
+assert_equal(notices[#notices], "Video added to history db", "successful add_video should notify")