feat(api): NodeRegistry + ConnectionProviderRegistry (DI-collected)

src/VolcanicCore.Api/Program.cs

@@ -2,6 +2,8 @@ using Microsoft.AspNetCore.Authentication.Cookies;
 using VolcanicCore.Api;
 using VolcanicCore.Api.Auth;
 using VolcanicCore.Api.Endpoints;
+using VolcanicCore.Api.Registries;
+using VolcanicCore.Core;
 using VolcanicCore.Persistence;
 using VolcanicCore.Persistence.Migrations;
 using VolcanicCore.Persistence.Repositories;
@@ -59,6 +61,14 @@ builder.Services
     });
 builder.Services.AddAuthorization();
 
+// Reflection scan — pick up INodeType / IConnectionProvider implementations
+// registered as DI services by any loaded assembly. In Plan 2, node/provider
+// assemblies will register their types via extension methods.
+builder.Services.AddSingleton<NodeRegistry>(sp =>
+    new NodeRegistry(sp.GetServices<INodeType>()));
+builder.Services.AddSingleton<ConnectionProviderRegistry>(sp =>
+    new ConnectionProviderRegistry(sp.GetServices<IConnectionProvider>()));
+
 var app = builder.Build();
 
 // Apply migrations at boot.

src/VolcanicCore.Api/Registries/ConnectionProviderRegistry.cs

@@ -0,0 +1,23 @@
+using VolcanicCore.Core;
+
+namespace VolcanicCore.Api.Registries;
+
+public sealed class ConnectionProviderRegistry
+{
+    private readonly IReadOnlyDictionary<string, IConnectionProvider> _byId;
+    public IReadOnlyList<IConnectionProvider> All { get; }
+
+    public ConnectionProviderRegistry(IEnumerable<IConnectionProvider> providers)
+    {
+        All = providers.ToArray();
+        var byId = new Dictionary<string, IConnectionProvider>(StringComparer.Ordinal);
+        foreach (var p in All)
+            if (!byId.TryAdd(p.Id, p))
+                throw new InvalidOperationException($"Duplicate connection provider id: {p.Id}");
+        _byId = byId;
+    }
+
+    public IConnectionProvider Get(string id) =>
+        _byId.TryGetValue(id, out var p) ? p
+            : throw new KeyNotFoundException($"Unknown connection provider: {id}");
+}

src/VolcanicCore.Api/Registries/NodeRegistry.cs

@@ -0,0 +1,25 @@
+using VolcanicCore.Core;
+
+namespace VolcanicCore.Api.Registries;
+
+public sealed class NodeRegistry
+{
+    private readonly IReadOnlyDictionary<string, INodeType> _byId;
+    public IReadOnlyList<INodeType> All { get; }
+
+    public NodeRegistry(IEnumerable<INodeType> nodes)
+    {
+        All = nodes.ToArray();
+        var byId = new Dictionary<string, INodeType>(StringComparer.Ordinal);
+        foreach (var n in All)
+        {
+            if (!byId.TryAdd(n.Id, n))
+                throw new InvalidOperationException($"Duplicate node type id: {n.Id}");
+        }
+        _byId = byId;
+    }
+
+    public INodeType Get(string id) =>
+        _byId.TryGetValue(id, out var n) ? n
+            : throw new KeyNotFoundException($"Unknown node type: {id}");
+}

tests/VolcanicCore.Tests/ConnectionProviderRegistryTests.cs

@@ -0,0 +1,25 @@
+using System.Text.Json;
+using VolcanicCore.Api.Registries;
+using VolcanicCore.Core;
+
+namespace VolcanicCore.Tests;
+
+public class ConnectionProviderRegistryTests
+{
+    private sealed class FakeProvider : IConnectionProvider
+    {
+        public string Id => "test.provider";
+        public string DisplayName => "Fake";
+        public JsonSchema ConfigSchema => new(JsonDocument.Parse("{}").RootElement);
+        public Task<object> OpenAsync(JsonElement config, CancellationToken ct) => Task.FromResult<object>(new());
+        public Task CloseAsync(object handle) => Task.CompletedTask;
+    }
+
+    [Fact]
+    public void Registers_and_looks_up_by_id()
+    {
+        var reg = new ConnectionProviderRegistry(new IConnectionProvider[] { new FakeProvider() });
+        Assert.Single(reg.All);
+        Assert.Same(reg.All[0], reg.Get("test.provider"));
+    }
+}

tests/VolcanicCore.Tests/NodeRegistryTests.cs

@@ -0,0 +1,38 @@
+using System.Text.Json;
+using VolcanicCore.Api.Registries;
+using VolcanicCore.Core;
+
+namespace VolcanicCore.Tests;
+
+public class NodeRegistryTests
+{
+    private sealed class FakeAction : IActionNode
+    {
+        public string Id => "test.echo";
+        public string DisplayName => "Echo";
+        public NodeCategory Category => NodeCategory.Action;
+        public int InputCount => 1;
+        public int OutputCount => 1;
+        public string? ConnectionProviderId => null;
+        public JsonSchema ConfigSchema => new(JsonDocument.Parse("{}").RootElement);
+        public Task<IReadOnlyList<IReadOnlyList<Item>>> ExecuteAsync(
+            INodeContext ctx, IReadOnlyList<IReadOnlyList<Item>> inputsByPort, CancellationToken ct)
+            => Task.FromResult<IReadOnlyList<IReadOnlyList<Item>>>(new[] { inputsByPort[0] });
+    }
+
+    [Fact]
+    public void Registers_instances_and_looks_them_up_by_id()
+    {
+        var reg = new NodeRegistry(new INodeType[] { new FakeAction() });
+        Assert.Single(reg.All);
+        Assert.Same(reg.All[0], reg.Get("test.echo"));
+        Assert.Throws<KeyNotFoundException>(() => reg.Get("does.not.exist"));
+    }
+
+    [Fact]
+    public void Duplicate_ids_throw()
+    {
+        Assert.Throws<InvalidOperationException>(() =>
+            new NodeRegistry(new INodeType[] { new FakeAction(), new FakeAction() }));
+    }
+}