Phase 0 WP-0.2–0.9: Implement Commons (types, entities, interfaces, messages, protocol, tests)

- WP-0.2: Namespace/folder skeleton (26 directories)
- WP-0.3: Shared data types (6 enums, RetryPolicy, Result<T>)
- WP-0.4: 24 domain entity POCOs across 10 domain areas
- WP-0.5: 7 repository interfaces with full CRUD signatures
- WP-0.6: IAuditService cross-cutting interface
- WP-0.7: 26 message contract records across 8 concern areas
- WP-0.8: IDataConnection protocol abstraction with batch ops
- WP-0.9: 8 architectural constraint enforcement tests
All 40 tests pass, zero warnings.

src/ScadaLink.Commons/Messages/Artifacts/ArtifactDeploymentResponse.cs

@@ -0,0 +1,8 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record ArtifactDeploymentResponse(
+    string DeploymentId,
+    string SiteId,
+    bool Success,
+    string? ErrorMessage,
+    DateTimeOffset Timestamp);

src/ScadaLink.Commons/Messages/Artifacts/DatabaseConnectionArtifact.cs

@@ -0,0 +1,7 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record DatabaseConnectionArtifact(
+    string Name,
+    string ConnectionString,
+    int MaxRetries,
+    TimeSpan RetryDelay);

src/ScadaLink.Commons/Messages/Artifacts/DeployArtifactsCommand.cs

@@ -0,0 +1,9 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record DeployArtifactsCommand(
+    string DeploymentId,
+    IReadOnlyList<SharedScriptArtifact>? SharedScripts,
+    IReadOnlyList<ExternalSystemArtifact>? ExternalSystems,
+    IReadOnlyList<DatabaseConnectionArtifact>? DatabaseConnections,
+    IReadOnlyList<NotificationListArtifact>? NotificationLists,
+    DateTimeOffset Timestamp);

src/ScadaLink.Commons/Messages/Artifacts/ExternalSystemArtifact.cs

@@ -0,0 +1,8 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record ExternalSystemArtifact(
+    string Name,
+    string EndpointUrl,
+    string AuthType,
+    string? AuthConfiguration,
+    string? MethodDefinitionsJson);

src/ScadaLink.Commons/Messages/Artifacts/NotificationListArtifact.cs

@@ -0,0 +1,5 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record NotificationListArtifact(
+    string Name,
+    IReadOnlyList<string> RecipientEmails);

src/ScadaLink.Commons/Messages/Artifacts/SharedScriptArtifact.cs

@@ -0,0 +1,7 @@
+namespace ScadaLink.Commons.Messages.Artifacts;
+
+public record SharedScriptArtifact(
+    string Name,
+    string Code,
+    string? ParameterDefinitions,
+    string? ReturnDefinition);