Basic Plaid Integration (#1433)

* Basic plaid data model and linking

* Remove institutions, add plaid items

* Improve schema and Plaid provider

* Add webhook verification sketch

* Webhook verification

* Item accounts and balances sync setup

* Provide test encryption keys

* Fix test

* Only provide encryption keys in prod

* Try defining keys in test env

* Consolidate account sync logic

* Add back plaid account initialization

* Plaid transaction sync

* Sync UI overhaul for Plaid

* Add liability and investment syncing

* Handle investment webhooks and process current day holdings

* Remove logs

* Remove "all" period select for performance

* fix amount calc

* Remove todo comment

* Coming soon for investment historical data

* Document Plaid configuration

* Listen for holding updates

app/javascript/controllers/plaid_controller.js

@@ -0,0 +1,52 @@
+import { Controller } from "@hotwired/stimulus";
+
+// Connects to data-controller="plaid"
+export default class extends Controller {
+  static values = {
+    linkToken: String,
+  };
+
+  open() {
+    const handler = Plaid.create({
+      token: this.linkTokenValue,
+      onSuccess: this.handleSuccess,
+      onLoad: this.handleLoad,
+      onExit: this.handleExit,
+      onEvent: this.handleEvent,
+    });
+
+    handler.open();
+  }
+
+  handleSuccess(public_token, metadata) {
+    fetch("/plaid_items", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        "X-CSRF-Token": document.querySelector('[name="csrf-token"]').content,
+      },
+      body: JSON.stringify({
+        plaid_item: {
+          public_token: public_token,
+          metadata: metadata,
+        },
+      }),
+    }).then((response) => {
+      if (response.redirected) {
+        window.location.href = response.url;
+      }
+    });
+  }
+
+  handleExit(err, metadata) {
+    // no-op
+  }
+
+  handleEvent(eventName, metadata) {
+    // no-op
+  }
+
+  handleLoad() {
+    // no-op
+  }
+}