feat(ui): add remote-control URLs + fix header typos and env

Add support for displaying local remote-control URLs and QR code in the
Settings UI, including styles for URL list, row layout, monospaced links,
and a QR container. Expose a new global API signature getLocalIpAddresses
for retrieving local IPs.

Fix several UI issues:
- Correct typo in header method name (opedAddPlaylistDialog -> openAddPlaylistDialog).
- Fix malformed GitHub URL and collapse img tag formatting.
- Reformat imports and viewChild usage for readability.

Change local development backend URL to localhost:3000 in the local
environment to point to the running local API during development.

These changes improve developer ergonomics (local backend), add a remote
control discovery UX for users on the same network, and tidy up header
bugs and formatting.

apps/web/src/app/shared/components/header/header.component.ts

@@ -1,4 +1,13 @@
-import { Component, HostBinding, OnInit, effect, inject, input, output, viewChild } from '@angular/core';
+import {
+    Component,
+    HostBinding,
+    OnInit,
+    effect,
+    inject,
+    input,
+    output,
+    viewChild,
+} from '@angular/core';
 import { FormsModule, ReactiveFormsModule } from '@angular/forms';
 import { MatButtonModule } from '@angular/material/button';
 import { MatCheckboxModule } from '@angular/material/checkbox';
@@ -12,8 +21,8 @@ import { Store } from '@ngrx/store';
 import { TranslateModule } from '@ngx-translate/core';
 import { DataService, SortBy, SortOrder, SortService } from 'services';
 //import { shell } from 'electron';
-import { selectActiveTypeFilters, setSelectedFilters } from 'm3u-state';
 import { AddPlaylistMenuComponent, PlaylistType } from 'components';
+import { selectActiveTypeFilters, setSelectedFilters } from 'm3u-state';
 import { HomeComponent } from '../../../home/home.component';
 import { AboutDialogComponent } from '../about-dialog/about-dialog.component';
 import { AddPlaylistDialogComponent } from '../add-playlist/add-playlist-dialog.component';
@@ -47,7 +56,9 @@ export class HeaderComponent implements OnInit {
     private store = inject(Store);
     private sortService = inject(SortService);
 
-    readonly addPlaylistMenuComponent = viewChild.required(AddPlaylistMenuComponent);
+    readonly addPlaylistMenuComponent = viewChild.required(
+        AddPlaylistMenuComponent
+    );
     readonly isDesktop = !!window.electron;
     readonly title = input.required<string>();
     readonly subtitle = input.required<string>();
@@ -133,7 +144,7 @@ export class HeaderComponent implements OnInit {
         });
     }
 
-    opedAddPlaylistDialog(type: PlaylistType) {
+    openAddPlaylistDialog(type: PlaylistType) {
         this.dialog.open<AddPlaylistDialogComponent, { type: PlaylistType }>(
             AddPlaylistDialogComponent,
             {