Reduce hot run polling pressure

platform/repo/resources_test.go

@@ -1,6 +1,7 @@
 package repo
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"os"
@@ -306,6 +307,56 @@ func TestMySQLSnapshotRoundTripsDurableJobSchedulingMetadata(t *testing.T) {
 	}
 }
 
+func TestFileStorePersistsRunRuntimeStateSeparately(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "metadata.json")
+	store, err := NewFileStore(path)
+	if err != nil {
+		t.Fatalf("create file store: %v", err)
+	}
+	stamp := time.Date(2026, 7, 18, 10, 0, 0, 0, time.UTC)
+	if err := store.PluginDataRecords().Create(domain.PluginDataRecord{ID: "plugin-record-1", PluginID: "server.scum", ServerInstanceID: "server-1", Collection: "players", Key: "steam-1", Value: map[string]any{"displayName": "Ada"}, CreatedAt: stamp, UpdatedAt: stamp}); err != nil {
+		t.Fatalf("create plugin data: %v", err)
+	}
+	mainBefore, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read main snapshot before runtime update: %v", err)
+	}
+
+	endpoint := domain.RunEndpoint{ID: "run-runtime", DisplayName: "Runtime Run", Version: "1.0.0", Platform: "linux", Architecture: "amd64", Status: domain.RunEndpointStatusOnline, Capacity: domain.RunCapacity{MaxJobs: 4}, LastHeartbeatAt: stamp}
+	if err := store.RunEndpoints().Create(endpoint); err != nil {
+		t.Fatalf("create runtime endpoint: %v", err)
+	}
+	session := domain.RunControlSession{RunEndpointID: endpoint.ID, SessionToken: "raw-runtime-token", SessionTokenHash: strings.Repeat("a", 64), Status: domain.AuthSessionStatusActive, Generation: 1, CapabilityFingerprint: "cap-runtime", HeartbeatIntervalSeconds: 15, CreatedAt: stamp, UpdatedAt: stamp, ExpiresAt: stamp.Add(time.Hour), RequireSignedRequests: true, UsedNonces: []string{"nonce-1"}}
+	if err := store.RunControlSessions().Create(session); err != nil {
+		t.Fatalf("create runtime session: %v", err)
+	}
+	mainAfter, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read main snapshot after runtime update: %v", err)
+	}
+	if !bytes.Equal(mainBefore, mainAfter) {
+		t.Fatalf("runtime updates rewrote the main metadata snapshot")
+	}
+	runtimePayload, err := os.ReadFile(runtimeMetadataPath(path))
+	if err != nil {
+		t.Fatalf("read runtime snapshot: %v", err)
+	}
+	if !strings.Contains(string(runtimePayload), endpoint.ID) || strings.Contains(string(runtimePayload), session.SessionToken) {
+		t.Fatalf("unexpected runtime snapshot payload: %s", runtimePayload)
+	}
+
+	reloaded, err := NewFileStore(path)
+	if err != nil {
+		t.Fatalf("reload file store: %v", err)
+	}
+	if got, err := reloaded.RunEndpoints().Get(endpoint.ID); err != nil || got.Version != endpoint.Version {
+		t.Fatalf("runtime endpoint did not reload: %+v err=%v", got, err)
+	}
+	if got, err := reloaded.RunControlSessions().Get(endpoint.ID); err != nil || got.SessionTokenHash != session.SessionTokenHash || got.UsedNonces[0] != "nonce-1" {
+		t.Fatalf("runtime session did not reload: %+v err=%v", got, err)
+	}
+}
+
 func TestFileStorePersistsPluginOperationsStateAcrossRestart(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "plugin-operations.json")
 	store, err := NewFileStore(path)