expose Ignis API, implement shared ws client

packages/shim/src/ignis-api.js

@@ -0,0 +1,28 @@
+// Public Ignis API surface. The documented way for plugins (and Ignis-internal code) to reach shim services.
+// WIP, may expand to cover more shared functionality.
+
+export function installIgnisApi(wsClient) {
+  window.__ignis = window.__ignis || {};
+
+  // Live getters so vault info reflects whatever init.js / vault-switch code has set.
+  Object.defineProperty(window.__ignis, "vault", {
+    get() {
+      return {
+        id: window.__currentVaultId || null,
+        path: window.__vaultConfig?.path || null,
+      };
+    },
+    enumerable: true,
+    configurable: true,
+  });
+
+  window.__ignis.ws = {
+    subscribe: wsClient.subscribe,
+    send: wsClient.send,
+    channel: wsClient.channel,
+    isOpen: wsClient.isOpen,
+    onStateChange: wsClient.onStateChange,
+  };
+
+  window.__ignis.plugins = window.__ignis.plugins || {};
+}