fix: 保证 Web observer 有界收尾

复用 stop-once 生命周期覆盖成功、失败、部分启动与异常兜底路径。\n\n将 YAML 派生的 maxRun/maxSamples 投影到 manifest 和 heartbeat，并补齐聚焦回归测试。

scripts/src/hwlab-node/web-probe-observe-options.test.ts

@@ -171,6 +171,22 @@ test("observe start selects the YAML public origin semantically", () => {
   assert.equal(options.browserProxyModeSource, "yaml-origin");
 });
 
+test("observe start inherits finite observer lifecycle limits from the owning YAML", () => {
+  const options = parseNodeWebProbeObserveOptions(
+    ["start"],
+    "NC01",
+    "v03",
+    spec,
+    null,
+    null,
+  );
+
+  assert.equal(options.maxRunSeconds, 3600);
+  assert.equal(options.maxSamples, 720);
+  assert.ok(options.maxRunSeconds > 0);
+  assert.ok(options.maxSamples > 0);
+});
+
 test("observe start refuses URL-based internal/public selection ambiguity", () => {
   assert.throws(
     () => parseNodeWebProbeObserveOptions(