agent: unify listening and dialing with directed mutual measurements

Replace Probe with Agent across node runtime, Fleet contracts, backend state, API and storage. Report incoming sessions and outgoing link health through each Agent uplink, and retain directed link controls and retry.

Update protocol fixtures and end-to-end coverage for the unified model; accept requested cancellation during the Fleet timeout test cleanup.

backend/tests/MoShiro.Backend.Tests/ArchitectureTests.cs

@@ -99,16 +99,12 @@ public sealed class ArchitectureTests
         Assert.DoesNotContain(agent.ProjectReferences, r => r.StartsWith("MoShiro.Backend", StringComparison.Ordinal) || r.StartsWith("Fleet.Server", StringComparison.Ordinal) || r.StartsWith("Fleet.Enrollment", StringComparison.Ordinal));
         Assert.Equal(["Fleet.Hosting", "Fleet.Link", "MoShiro.Measurement"], agent.ProjectReferences.Order().ToArray());
 
-        // Probe 同理，并且不认识 Backend 和 Agent
-        Project probe = Get("MoShiro.Probe");
-        Assert.Equal(["Fleet.Hosting", "Fleet.Link", "MoShiro.Measurement"], probe.ProjectReferences.Order().ToArray());
-
         // 两个节点的共享库只依赖协议
         // 测量库在 TCP 数据面上做预握手敲门，所以直接引用 Fleet.Identity（节点侧库）
         Assert.Equal(["Fleet.Identity", "MoShiro.Protocol"], Get("MoShiro.Measurement").ProjectReferences.Order().ToArray());
 
         // 节点一侧的库没有运行时依赖包，并使用节点禁用列表（不能用 HttpClient、Process、写文件；唯一的写文件豁免在 ConfigStore）
-        foreach (string name in new[] { "Fleet.Link", "Fleet.Hosting", "MoShiro.Measurement", "MoShiro.Agent", "MoShiro.Probe" })
+        foreach (string name in new[] { "Fleet.Link", "Fleet.Hosting", "MoShiro.Measurement", "MoShiro.Agent" })
         {
             Project project = Get(name);
             Assert.All(project.Packages, package => Assert.Contains(package, s_allowedAnalyzers));
@@ -126,9 +122,9 @@ public sealed class ArchitectureTests
     [Fact]
     public void CollectionLayer_KnowsNoBusinessProtocolsOrPlans_OnlyMechanismsAndRawColumns()
     {
-        // 采集层（协议、积木、Agent、Probe、Fleet）只认识机制（传输、节奏、方向、时间戳）和原始列；
+        // 采集层（协议、积木、Agent、Fleet）只认识机制（传输、节奏、方向、时间戳）和原始列；
         // REALITY、Hysteria2、Minecraft 这些业务概念以及由原语编排成的测试方案只存在于 Backend。
-        string[] collectionRoots = ["shared/MoShiro.Protocol", "shared/MoShiro.Measurement", "agent/src", "probe/src", "fleet/src"];
+        string[] collectionRoots = ["shared/MoShiro.Protocol", "shared/MoShiro.Measurement", "agent/src", "fleet/src"];
         string[] forbidden = ["reality", "hysteria", "hy2", "minecraft", "brutal", "PlanSpec", "PhaseSpec"];
         foreach (string root in collectionRoots)
         {