fix(shell): dismiss the wizard when a library exists

The first-run wizard dismissed itself as a step in its own flow, so a
library appearing by any other route left a full-screen modal up over
an app that was already set up — intercepting every pointer event,
which is also what keeps Settings out of reach while it is there.

AddLibrary emits LibraryAdded whoever calls it, so one subscription
makes the dismissal follow the state the wizard exists to wait for
rather than the button being pressed. It is registered before the
initial read, or a library arriving while that call is in flight is
answered with a stale empty list; both routes out now end in one
dismiss(), which sets `finished` before asking the dialog to close
because preventClose cancels the hide otherwise.

Closes #175

frontend/src/components/first-run-wizard/first-run-wizard.ts

@@ -2,12 +2,14 @@ import { LitElement, html, css, nothing } from 'lit';
 import { customElement, state, query } from 'lit/decorators.js';
 import '@awesome.me/webawesome/dist/components/dialog/dialog.js';
 import '@awesome.me/webawesome/dist/components/icon/icon.js';
+import { EventsOn } from '@runtime/runtime';
 import {
     AddLibrary,
     GetAllLibrariesWithTrackCounts,
 } from '@go/library/library.js';
 import { describeError, explainError } from '@utils/describe-error';
 import { nameDialogsIn } from '@utils/name-dialog';
+import { Events } from '../../events';
 import { pickDirectory } from '../../utils/pick-directory';
 
 /**
@@ -19,6 +21,13 @@ import { pickDirectory } from '../../utils/pick-directory';
  * prompting the user to pick their music folder, registers it through the
  * library CRUD API, and dismisses itself.  AddLibrary emits LibraryAdded
  * and kicks off the initial scan automatically.
+ *
+ * **The dismissal follows the library existing, not the button being
+ * pressed.** `AddLibrary` emits `LibraryAdded` whoever calls it, so the
+ * wizard waits on the state it exists to wait for rather than on a step
+ * in its own flow — a library arriving by any other route (Settings, a
+ * direct call) leaves a full-screen modal up otherwise, intercepting
+ * every pointer event.
  */
 @customElement('first-run-wizard')
 export class FirstRunWizard extends LitElement {
@@ -37,9 +46,18 @@ export class FirstRunWizard extends LitElement {
     /** Error message from a failed pick/save, if any. */
     @state() private errorMessage = '';
 
+    /** Unsubscribe from LibraryAdded, while this element is connected. */
+    private cancelLibraryAdded?: () => void;
+
     override async connectedCallback(): Promise<void> {
         super.connectedCallback();
 
+        // Subscribed before the read below, so a library arriving while
+        // that call is in flight is not answered with a stale empty list.
+        this.cancelLibraryAdded = EventsOn(Events.LibraryAdded, () => {
+            this.dismiss();
+        });
+
         try {
             const existing = await GetAllLibrariesWithTrackCounts();
 
@@ -54,6 +72,8 @@ export class FirstRunWizard extends LitElement {
             return;
         }
 
+        if (this.finished) return;
+
         this.active = true;
 
         await this.updateComplete;
@@ -61,6 +81,13 @@ export class FirstRunWizard extends LitElement {
         if (this.dialog) this.dialog.open = true;
     }
 
+    override disconnectedCallback(): void {
+        this.cancelLibraryAdded?.();
+        this.cancelLibraryAdded = undefined;
+
+        super.disconnectedCallback();
+    }
+
     static override styles = css`
         wa-dialog {
             --width: 480px;
@@ -239,6 +266,20 @@ export class FirstRunWizard extends LitElement {
         if (!this.finished) e.preventDefault();
     };
 
+    /**
+     * Close, and stay closed: a library exists, so setup is over.
+     *
+     * `finished` is set first, or `preventClose` cancels the hide this
+     * asks for.
+     */
+    private dismiss(): void {
+        this.finished = true;
+
+        if (this.dialog) this.dialog.open = false;
+
+        this.active = false;
+    }
+
     private handleChoose = async (): Promise<void> => {
         this.errorMessage = '';
 
@@ -264,11 +305,7 @@ export class FirstRunWizard extends LitElement {
         try {
             await AddLibrary(this.selectedDirectory);
 
-            this.finished = true;
-
-            if (this.dialog) this.dialog.open = false;
-
-            this.active = false;
+            this.dismiss();
         } catch (err) {
             this.errorMessage = explainError(
                 err,