Phase 3B: Site I/O & Observability — Communication, DCL, Script/Alarm actors, Health, Event Logging

Communication Layer (WP-1–5):
- 8 message patterns with correlation IDs, per-pattern timeouts
- Central/Site communication actors, transport heartbeat config
- Connection failure handling (no central buffering, debug streams killed)

Data Connection Layer (WP-6–14, WP-34):
- Connection actor with Become/Stash lifecycle (Connecting/Connected/Reconnecting)
- OPC UA + LmxProxy adapters behind IDataConnection
- Auto-reconnect, bad quality propagation, transparent re-subscribe
- Write-back, tag path resolution with retry, health reporting
- Protocol extensibility via DataConnectionFactory

Site Runtime (WP-15–25, WP-32–33):
- ScriptActor/ScriptExecutionActor (triggers, concurrent execution, blocking I/O dispatcher)
- AlarmActor/AlarmExecutionActor (ValueMatch/RangeViolation/RateOfChange, in-memory state)
- SharedScriptLibrary (inline execution), ScriptRuntimeContext (API)
- ScriptCompilationService (Roslyn, forbidden API enforcement, execution timeout)
- Recursion limit (default 10), call direction enforcement
- SiteStreamManager (per-subscriber bounded buffers, fire-and-forget)
- Debug view backend (snapshot + stream), concurrency serialization
- Local artifact storage (4 SQLite tables)

Health Monitoring (WP-26–28):
- SiteHealthCollector (thread-safe counters, connection state)
- HealthReportSender (30s interval, monotonic sequence numbers)
- CentralHealthAggregator (offline detection 60s, online recovery)

Site Event Logging (WP-29–31):
- SiteEventLogger (SQLite, 6 event categories, ISO 8601 UTC)
- EventLogPurgeService (30-day retention, 1GB cap)
- EventLogQueryService (filters, keyword search, keyset pagination)

541 tests pass, zero warnings.

tests/ScadaLink.Communication.Tests/CommunicationOptionsTests.cs

@@ -0,0 +1,61 @@
+namespace ScadaLink.Communication.Tests;
+
+/// <summary>
+/// WP-2: Tests for per-pattern timeout configuration.
+/// </summary>
+public class CommunicationOptionsTests
+{
+    [Fact]
+    public void DefaultTimeouts_AreReasonable()
+    {
+        var options = new CommunicationOptions();
+
+        Assert.Equal(TimeSpan.FromMinutes(2), options.DeploymentTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(30), options.LifecycleTimeout);
+        Assert.Equal(TimeSpan.FromMinutes(1), options.ArtifactDeploymentTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(30), options.QueryTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(30), options.IntegrationTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(10), options.DebugViewTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(10), options.HealthReportTimeout);
+    }
+
+    [Fact]
+    public void TransportHeartbeat_HasExplicitDefaults()
+    {
+        var options = new CommunicationOptions();
+
+        // WP-3: Transport heartbeat is explicitly configured, not framework defaults
+        Assert.Equal(TimeSpan.FromSeconds(5), options.TransportHeartbeatInterval);
+        Assert.Equal(TimeSpan.FromSeconds(15), options.TransportFailureThreshold);
+    }
+
+    [Fact]
+    public void DeploymentTimeout_IsLongestPattern()
+    {
+        var options = new CommunicationOptions();
+
+        Assert.True(options.DeploymentTimeout > options.LifecycleTimeout);
+        Assert.True(options.DeploymentTimeout > options.QueryTimeout);
+        Assert.True(options.DeploymentTimeout > options.IntegrationTimeout);
+    }
+
+    [Fact]
+    public void AllTimeouts_AreConfigurable()
+    {
+        var options = new CommunicationOptions
+        {
+            DeploymentTimeout = TimeSpan.FromMinutes(5),
+            LifecycleTimeout = TimeSpan.FromMinutes(1),
+            ArtifactDeploymentTimeout = TimeSpan.FromMinutes(3),
+            QueryTimeout = TimeSpan.FromMinutes(1),
+            IntegrationTimeout = TimeSpan.FromMinutes(1),
+            DebugViewTimeout = TimeSpan.FromSeconds(30),
+            HealthReportTimeout = TimeSpan.FromSeconds(30),
+            TransportHeartbeatInterval = TimeSpan.FromSeconds(2),
+            TransportFailureThreshold = TimeSpan.FromSeconds(10)
+        };
+
+        Assert.Equal(TimeSpan.FromMinutes(5), options.DeploymentTimeout);
+        Assert.Equal(TimeSpan.FromSeconds(2), options.TransportHeartbeatInterval);
+    }
+}