feat(health-check): introduce health probe gap configuration and enhance health check logic

Added `healthProbeGapMs` configuration to control the minimum pause between probes to different physical targets. Updated health check service to utilize this configuration, ensuring efficient probing without overwhelming the targets. Enhanced the `runAllChecks` function to group probes by physical IP and implement the new gap logic. Updated related tests to validate the new functionality.

apps/api/test/health-check.test.ts

@@ -17,7 +17,7 @@ function startTcpServer(): Promise<{ server: Server; port: number }> {
 }
 
 describe("health-check URL helpers", () => {
-  it("buildHttpProbeUrl uses FQDN in URL (IP pinned via DNS interceptor)", () => {
+  it("buildHttpProbeUrl uses FQDN in URL (IP pinned via connector)", () => {
     expect(
       healthCheckService.buildHttpProbeUrl("gt.rkns.top", 443, "/", true),
     ).toBe("https://gt.rkns.top/");
@@ -125,6 +125,28 @@ describe("health-check probeTarget", () => {
       await new Promise<void>((resolve) => httpServer.close(() => resolve()));
     }
   });
+
+  it("physicalProbeKey collapses group+binding on same IP for tcp", async () => {
+    const { physicalProbeKey } = await import("../src/services/health-check-service.js");
+    const group: HealthCheckTarget = {
+      scope: "group",
+      ref_id: 1,
+      ip: "93.115.203.183",
+      hostname: "gt.rkns.top",
+      type: "tcp",
+      port: 443,
+      path: null,
+      expected_status: null,
+      timeout_ms: 3000,
+    };
+    const binding: HealthCheckTarget = {
+      ...group,
+      scope: "binding",
+      ref_id: 2,
+      hostname: "rutg.rkns.top",
+    };
+    expect(physicalProbeKey(group)).toBe(physicalProbeKey(binding));
+  });
 });
 
 describe("health-check state derivation via runAllChecks", () => {