Nucleic: Windows Port 1

NucleicBroker/AiProvider.cs

@@ -0,0 +1,28 @@
+using System.Text.Json;
+
+namespace NucleicBroker;
+
+/// <summary>
+/// The `ai.generate` seam (docs/WINDOWS_PORT.md §9.2): Phi Silica via Windows AI Foundry is
+/// WinRT-only, so hostd routes on-device-AI requests through this broker rather than a
+/// second helper process. Capability-probed: on non-Copilot+ hardware (or off-Windows) the
+/// provider is unavailable and hostd's Intelligence seam falls back to its heuristics —
+/// identical UX to a Mac without Apple Intelligence.
+/// </summary>
+public interface IAiProvider
+{
+    bool IsAvailable { get; }
+    /// <summary>Generate text for `prompt`; when `schema` is present the result must be JSON
+    /// conforming to it (guided generation). Throws WslcError(AiUnavailable) when absent.</summary>
+    Task<string> GenerateAsync(string prompt, JsonElement? schema, CancellationToken ct);
+}
+
+/// <summary>Default provider: no on-device model. The real Foundry-backed provider lands
+/// with work item 16 behind the same interface.</summary>
+public sealed class UnavailableAiProvider : IAiProvider
+{
+    public bool IsAvailable => false;
+
+    public Task<string> GenerateAsync(string prompt, JsonElement? schema, CancellationToken ct) =>
+        throw new WslcError(WslcError.AiUnavailable, "no on-device AI provider on this machine");
+}