fix(cli): show group help

cli/tjwater-cli

@@ -180,6 +180,18 @@ async function main() {
     return 0;
   }
 
+  if (isLocalHelpCommand(parsed.command)) {
+    const result = await dispatch(parsed, null);
+    emitSuccess({
+      summary: result.summary,
+      data: result.local,
+      ctx: null,
+      durationMs: 0,
+      nextCommands: result.nextCommands,
+    });
+    return 0;
+  }
+
   const ctx = await buildContext(parsed.global);
   const startedAt = Date.now();
   const result = await dispatch(parsed, ctx);
@@ -194,14 +206,27 @@ async function main() {
   return 0;
 }
 
+function isLocalHelpCommand(command) {
+  if (command.length === 1 && GROUPS[command[0]]) return true;
+  return command.length > 1 && command.at(-1) === "help";
+}
+
 async function dispatch(parsed, ctx) {
   const [group, ...rest] = parsed.command;
   if (group === "network") {
+    if (rest.length === 0 || rest[0] === "help") return helpResult(["network"], NETWORK_COMMANDS);
     return commandFromMap(NETWORK_COMMANDS, rest, parsed, ctx);
   }
   if (group === "component" && rest[0] === "option") {
+    if (rest.length === 1 || rest[1] === "help") return helpResult(["component", "option"], {
+      schema: { summary: "读取选项 schema" },
+      get: { summary: "读取选项属性" },
+    });
     return componentOption(rest.slice(1), parsed, ctx);
   }
+  if (group === "component" && (rest.length === 0 || rest[0] === "help")) {
+    return helpResult(["component"], { option: { summary: GROUPS.component } });
+  }
   if (group === "simulation" && rest[0] === "run") {
     requireOptions(parsed.args, { "start-time": { required: true }, duration: { required: true } });
     const start = parseTime(parsed.args["start-time"], "--start-time");
@@ -218,10 +243,24 @@ async function dispatch(parsed, ctx) {
       ],
     };
   }
+  if (group === "simulation" && (rest.length === 0 || rest[0] === "help")) {
+    return helpResult(["simulation"], { run: { summary: "触发指定绝对时间的模拟运行" } });
+  }
   if (group === "analysis") {
+    if (rest.length === 0 || rest[0] === "help") return helpResult(["analysis"], {
+      age: { summary: "执行水龄分析" },
+      leakage: { summary: "漏损分析相关命令" },
+      "burst-detection": { summary: "爆管检测相关命令" },
+      "sensor-placement": { summary: "传感器选址相关命令" },
+    });
     return analysis(rest, parsed, ctx);
   }
   if (group === "data") {
+    if (rest.length === 0 || rest[0] === "help") return helpResult(["data"], {
+      timeseries: { summary: "时序数据查询命令" },
+      scada: { summary: "SCADA 元数据查询命令" },
+      scheme: { summary: "方案数据查询命令" },
+    });
     return dataCommand(rest, parsed, ctx);
   }
   throw cliError("未找到命令", "COMMAND_NOT_FOUND", `unknown command: ${parsed.command.join(" ")}`, 2, {
@@ -229,6 +268,19 @@ async function dispatch(parsed, ctx) {
   });
 }
 
+function helpResult(command, commands) {
+  return {
+    summary: `命令帮助：${command.join(" ")}`,
+    local: {
+      command: command.join(" "),
+      commands: Object.fromEntries(
+        Object.entries(commands).map(([name, spec]) => [name, spec.summary ?? ""]),
+      ),
+      examples: examplesFor(command),
+    },
+  };
+}
+
 function commandFromMap(map, commandPath, parsed, ctx) {
   const name = commandPath[0];
   const spec = map[name];
@@ -383,6 +435,9 @@ function dataCommand(rest, parsed, ctx) {
 }
 
 async function requestJson(ctx, request) {
+  if (request.local !== undefined) {
+    return request.local;
+  }
   if (request.requireProject) {
     requireProject(ctx);
   }
@@ -557,15 +612,45 @@ function emitSuccess({ summary, data, ctx, durationMs, nextCommands }) {
     schema_version: SCHEMA_VERSION,
     summary,
     data,
-    metadata: {
-      server: ctx.server,
-      request_id: ctx.requestId,
-      duration_ms: durationMs,
-    },
+    metadata: ctx
+      ? {
+          server: ctx.server,
+          request_id: ctx.requestId,
+          duration_ms: durationMs,
+        }
+      : undefined,
     next_commands: nextCommands,
   }));
 }
 
+function examplesFor(command) {
+  const key = command.join(" ");
+  const examples = {
+    network: [
+      "tjwater-cli network get-all-pipes-properties",
+      "tjwater-cli network get-pipe-properties --pipe P1",
+    ],
+    component: ["tjwater-cli component option help"],
+    "component option": [
+      "tjwater-cli component option schema --kind time",
+      "tjwater-cli component option get --kind network",
+    ],
+    simulation: [
+      "tjwater-cli simulation run --start-time 2025-01-01T00:00:00+08:00 --duration 30",
+    ],
+    analysis: [
+      "tjwater-cli analysis age --start-time 2025-01-01T00:00:00+08:00 --duration 900",
+      "tjwater-cli analysis leakage schemes list",
+    ],
+    data: [
+      "tjwater-cli data timeseries realtime links --start-time 2025-01-01T00:00:00+08:00 --end-time 2025-01-01T01:00:00+08:00",
+      "tjwater-cli data scada list",
+      "tjwater-cli data scheme list",
+    ],
+  };
+  return examples[key] ?? ["tjwater-cli help"];
+}
+
 function emitFailure(error) {
   const payload = {
     ok: false,