refactor: 优化代码质量，遵循 KISS 原则

- 移除自签证书回退逻辑，简化为仅使用 AnyIP 证书
- 删除 internal/tls/generate.go（不再需要）
- 重构 main.go：提取初始化逻辑，main() 从 156 行降至 13 行
- 重构 internal/ws/handler.go：提取消息处理，handleConn() 从 131 行降至 25 行
- 重构 internal/config/load.go：使用 map 驱动消除重复代码
- 优化前端 startRecording()：使用标准 AbortController API
- 优化前端 showToast()：预定义 DOM 元素，代码减少 50%

代码行数减少 90 行，复杂度显著降低，所有构建通过

web/app.ts

@@ -29,7 +29,7 @@ interface AppState {
 	connected: boolean;
 	recording: boolean;
 	pendingStart: boolean;
-	startCancelled: boolean;
+	abortController: AbortController | null;
 	audioCtx: AudioContext | null;
 	workletNode: AudioWorkletNode | null;
 	stream: MediaStream | null;
@@ -65,7 +65,7 @@ const state: AppState = {
 	connected: false,
 	recording: false,
 	pendingStart: false,
-	startCancelled: false,
+	abortController: null,
 	audioCtx: null,
 	workletNode: null,
 	stream: null,
@@ -128,20 +128,19 @@ function connectWS(): void {
 		micBtn.disabled = false;
 	};
 	ws.onmessage = (e: MessageEvent) => handleServerMsg(e.data);
-	ws.onclose = () => {
-		state.connected = false;
-		state.ws = null;
-		micBtn.disabled = true;
-		if (state.recording) stopRecording();
-		// Clean up pending async start on disconnect
-		if (state.pendingStart) {
-			state.pendingStart = false;
-			state.startCancelled = true;
-			micBtn.classList.remove("recording");
-		}
-		setStatus("disconnected", "已断开");
-		scheduleReconnect();
-	};
+ws.onclose = () => {
+	state.connected = false;
+	state.ws = null;
+	micBtn.disabled = true;
+	if (state.recording) stopRecording();
+	if (state.pendingStart) {
+		state.abortController?.abort();
+		state.pendingStart = false;
+		micBtn.classList.remove("recording");
+	}
+	setStatus("disconnected", "已断开");
+	scheduleReconnect();
+};
 	ws.onerror = () => ws.close();
 	state.ws = ws;
 }
@@ -199,25 +198,14 @@ function setPreview(text: string, isFinal: boolean): void {
 	previewBox.classList.toggle("active", !isFinal);
 }
 function showToast(msg: string): void {
-	let toast = document.getElementById("toast");
-	if (!toast) {
-		toast = document.createElement("div");
-		toast.id = "toast";
-		toast.style.cssText =
-			"position:fixed;bottom:calc(100px + var(--safe-bottom,0px));left:50%;" +
-			"transform:translateX(-50%);background:#222;color:#eee;padding:8px 18px;" +
-			"border-radius:20px;font-size:14px;z-index:999;opacity:0;transition:opacity .3s;";
-		document.body.appendChild(toast);
-	}
+	const toast = q("#toast");
 	toast.textContent = msg;
-	toast.style.opacity = "1";
-	clearTimeout(
-		(toast as HTMLElement & { _timer?: ReturnType<typeof setTimeout> })._timer,
-	);
-	(toast as HTMLElement & { _timer?: ReturnType<typeof setTimeout> })._timer =
-		setTimeout(() => {
-			toast.style.opacity = "0";
-		}, 2000);
+	toast.classList.add("show");
+	const timer = (toast as HTMLElement & { _timer?: ReturnType<typeof setTimeout> })._timer;
+	if (timer) clearTimeout(timer);
+	(toast as HTMLElement & { _timer?: ReturnType<typeof setTimeout> })._timer = setTimeout(() => {
+		toast.classList.remove("show");
+	}, 2000);
 }
 // ── Audio pipeline ──
 async function initAudio(): Promise<void> {
@@ -234,19 +222,19 @@ async function initAudio(): Promise<void> {
 async function startRecording(): Promise<void> {
 	if (state.recording || state.pendingStart) return;
 	state.pendingStart = true;
-	state.startCancelled = false;
+	const abortController = new AbortController();
+	state.abortController = abortController;
 	try {
 		await initAudio();
-		if (state.startCancelled) {
+		if (abortController.signal.aborted) {
 			state.pendingStart = false;
 			return;
 		}
 		const audioCtx = state.audioCtx as AudioContext;
-		// Ensure AudioContext is running (may suspend between recordings)
 		if (audioCtx.state === "suspended") {
 			await audioCtx.resume();
 		}
-		if (state.startCancelled) {
+		if (abortController.signal.aborted) {
 			state.pendingStart = false;
 			return;
 		}
@@ -257,7 +245,7 @@ async function startRecording(): Promise<void> {
 				channelCount: 1,
 			},
 		});
-		if (state.startCancelled) {
+		if (abortController.signal.aborted) {
 			stream.getTracks().forEach((t) => {
 				t.stop();
 			});
@@ -275,34 +263,33 @@ async function startRecording(): Promise<void> {
 		};
 		source.connect(worklet);
 		worklet.port.postMessage({ command: "start" });
-		// Don't connect worklet to destination (no playback)
 		state.workletNode = worklet;
 		state.pendingStart = false;
+		state.abortController = null;
 		state.recording = true;
 		sendJSON({ type: "start" });
 		micBtn.classList.add("recording");
 		setPreview("", false);
 	} catch (err) {
 		state.pendingStart = false;
+		state.abortController = null;
 		showToast(`麦克风错误: ${(err as Error).message}`);
 	}
 }
 function stopRecording(): void {
-	// Cancel pending async start if still initializing
 	if (state.pendingStart) {
-		state.startCancelled = true;
+		state.abortController?.abort();
+		state.abortController = null;
 		micBtn.classList.remove("recording");
 		return;
 	}
 	if (!state.recording) return;
 	state.recording = false;
-	// Stop worklet
 	if (state.workletNode) {
 		state.workletNode.port.postMessage({ command: "stop" });
 		state.workletNode.disconnect();
 		state.workletNode = null;
 	}
-	// Stop mic stream
 	if (state.stream) {
 		state.stream.getTracks().forEach((t) => {
 			t.stop();

web/index.html

@@ -42,6 +42,7 @@
             <p id="history-empty" class="placeholder">暂无记录</p>
         </section>
     </div>
+	<div id="toast" class="toast"></div>
 
     <script type="module" src="app.ts"></script>
 </body>

web/style.css

@@ -272,3 +272,22 @@ header h1 {
 	background: var(--border);
 	border-radius: 2px;
 }
+/* Toast */
+.toast {
+	position: fixed;
+	bottom: calc(100px + var(--safe-bottom, 0px));
+	left: 50%;
+	transform: translateX(-50%);
+	background: #222;
+	color: #eee;
+	padding: 8px 18px;
+	border-radius: 20px;
+	font-size: 14px;
+	z-index: 999;
+	opacity: 0;
+	transition: opacity 0.3s;
+	pointer-events: none;
+}
+.toast.show {
+	opacity: 1;
+}