feat(FN-3396): bundle Cursor CLI as a plugin provider with dashboard auth w

Merges FN-3396's full Cursor CLI provider integration (Steps 1–4): defines a CLI-backed provider contract, adds the `fusion-plugin-cursor-runtime` plugin package with process management and runtime probes, wires dashboard auth flows and UI (ProviderCard, onboarding modal, settings), and bundles the

Fusion-Task-Id: FN-3396

plugins/fusion-plugin-cursor-runtime/src/provider.ts

@@ -0,0 +1,16 @@
+import { discoverCursorModels } from "./process-manager.js";
+import { probeCursorBinary } from "./probe.js";
+
+export async function discoverCursorProviderModels() {
+  const probe = await probeCursorBinary();
+  if (!probe.available || !probe.binaryName) {
+    return { models: [], source: "probe", fallbackUsed: true, reason: probe.reason ?? "binary unavailable" };
+  }
+  const result = await discoverCursorModels(probe.binaryName);
+  return {
+    models: result.models.map((id) => ({ id, label: id })),
+    source: result.source,
+    fallbackUsed: result.fallbackUsed,
+    reason: result.reason,
+  };
+}