report and cache the endpoint tray version

The agent already reported agentversion but the interactive tray app, which ships and updates independently, had no reported version. The agent now reads the tray exe file version and reports it as trayversion; EndpointState caches it (migration 0011) and the Fleet card surfaces it beside Agent. The tray csproj gains an explicit Version so the file version is stamped. Groundwork for per-PC version surfacing and push-update targeting.

agent/ShopDbEndpointAgent.Core/Contracts.cs

@@ -19,6 +19,7 @@ public sealed class EndpointReport
     [JsonPropertyName("ipaddress")] public string? IpAddress { get; set; }
     [JsonPropertyName("machinenumber")] public string? MachineNumber { get; set; }
     [JsonPropertyName("agentversion")] public string? AgentVersion { get; set; }
+    [JsonPropertyName("trayversion")] public string? TrayVersion { get; set; }
     [JsonPropertyName("lastboottime")] public DateTimeOffset? LastBootTime { get; set; }
     [JsonPropertyName("uptimeseconds")] public long? UptimeSeconds { get; set; }
     [JsonPropertyName("idleseconds")] public long? IdleSeconds { get; set; }

agent/ShopDbEndpointAgent.Core/EndpointCollector.cs

@@ -37,6 +37,7 @@ public sealed class EndpointCollector : ICollector
         {
             Hostname = Environment.MachineName,
             AgentVersion = agentVersion,
+            TrayVersion = GetTrayVersion(),
             Adopt = adopt ? true : null,
             LoggedInUser = GetLoggedInUser(),
             SerialNumber = GetSerialNumber(),
@@ -65,6 +66,34 @@ public sealed class EndpointCollector : ICollector
         return report;
     }
 
+    // The interactive tray app ships and updates independently of this service,
+    // so the agent reports the tray's file version as its own field. Resolve the
+    // tray exe beside the agent first (the normal install layout), then the
+    // default install dir; degrade to null when it is absent or unreadable so a
+    // tray-less install simply omits the field rather than failing the report.
+    private const string TrayExeName = "shopdb-endpoint-tray.exe";
+    private const string DefaultInstallDir = @"C:\Program Files\ShopDB\EndpointAgent";
+
+    private string? GetTrayVersion()
+    {
+        try
+        {
+            var beside = Path.Combine(AppContext.BaseDirectory, TrayExeName);
+            var installed = Path.Combine(DefaultInstallDir, TrayExeName);
+            var trayExe = File.Exists(beside) ? beside
+                        : File.Exists(installed) ? installed
+                        : null;
+            if (trayExe is null)
+                return null;
+            return FileVersionInfo.GetVersionInfo(trayExe).FileVersion;
+        }
+        catch (Exception ex)
+        {
+            logger.LogDebug(ex, "could not resolve tray version");
+            return null;
+        }
+    }
+
     // Combined watch list: interactive processes (by image name) and Windows
     // services (by service key name). Both land in report.Services with a shared
     // {name, app, kind, state, running, count} shape so the server/UI renders

agent/ShopDbEndpointAgent.Tray/ShopDbEndpointAgent.Tray.csproj

@@ -8,6 +8,11 @@
 	<UseWindowsForms>true</UseWindowsForms>
 	<RootNamespace>ShopDbEndpointAgent.Tray</RootNamespace>
 	<AssemblyName>shopdb-endpoint-tray</AssemblyName>
+	<!-- 1.0.0: first explicitly stamped tray version. The tray and the agent
+		 service version independently (they are separate exes and can be pushed
+		 apart), so the tray carries its own <Version> and the agent reports it
+		 as trayversion alongside its own agentversion (AGENT-CONTRACT.md 2). -->
+	<Version>1.0.0</Version>
 	<InvariantGlobalization>true</InvariantGlobalization>
 	<RuntimeIdentifier>win-x64</RuntimeIdentifier>
 	<SelfContained>true</SelfContained>