feat(design-system): add reusable Dialog primitive

Standalone, OnPush. Backdrop click and Escape close, focus trap with
return-focus on close, role=dialog/aria-modal. Sizes sm/md/lg. Colors/
radius/shadow/spacing via existing tenant CSS vars with fallbacks.

src/app/shared/ui/dialog/dialog.component.html

@@ -0,0 +1,33 @@
+@if (open()) {
+  <div class="app-dialog-backdrop" (click)="handleBackdropClick()">
+    <div
+      #panel
+      class="app-dialog-panel"
+      [class.app-dialog-panel--sm]="size() === 'sm'"
+      [class.app-dialog-panel--md]="size() === 'md'"
+      [class.app-dialog-panel--lg]="size() === 'lg'"
+      role="dialog"
+      aria-modal="true"
+      [attr.aria-label]="titleText()"
+      tabindex="-1"
+      (click)="$event.stopPropagation()"
+    >
+      @if (titleText()) {
+        <div class="app-dialog-panel__header">
+          <h2 class="app-dialog-panel__title">{{ titleText() }}</h2>
+          <button
+            type="button"
+            class="app-dialog-panel__close"
+            (click)="requestClose()"
+            aria-label="Close dialog"
+          >
+            &times;
+          </button>
+        </div>
+      }
+      <div class="app-dialog-panel__body">
+        <ng-content />
+      </div>
+    </div>
+  </div>
+}

src/app/shared/ui/dialog/dialog.component.scss

@@ -0,0 +1,104 @@
+.app-dialog-backdrop {
+  position: fixed;
+  inset: 0;
+  z-index: 1000;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: var(--space-md, 1rem);
+  background: rgba(0, 0, 0, 0.5);
+  animation: app-dialog-fade-in var(--transition-normal, 200ms ease);
+}
+
+.app-dialog-panel {
+  width: 100%;
+  max-height: 90vh;
+  overflow-y: auto;
+  background: var(--bg-primary, #fff);
+  border-radius: var(--radius-lg, 10px);
+  box-shadow: var(--shadow-md, 0 8px 24px rgba(0, 0, 0, 0.16));
+  animation: app-dialog-scale-in var(--transition-normal, 200ms ease);
+
+  &:focus-visible {
+    outline: none;
+  }
+}
+
+.app-dialog-panel--sm {
+  max-width: 400px;
+}
+
+.app-dialog-panel--md {
+  max-width: 560px;
+}
+
+.app-dialog-panel--lg {
+  max-width: 800px;
+}
+
+.app-dialog-panel__header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--space-md, 1rem);
+  padding: var(--space-md, 1rem) var(--space-lg, 1.5rem);
+  border-bottom: 1px solid var(--border-color, #e4e4e7);
+}
+
+.app-dialog-panel__title {
+  margin: 0;
+  font-size: 1.125rem;
+  font-weight: 600;
+  color: var(--text-primary, #1f322d);
+}
+
+.app-dialog-panel__close {
+  border: none;
+  background: transparent;
+  color: var(--text-secondary, #6b7280);
+  font-size: 1.5rem;
+  line-height: 1;
+  cursor: pointer;
+  padding: var(--space-xs, 0.25rem);
+  border-radius: var(--radius-sm, 4px);
+
+  &:hover {
+    background: var(--bg-secondary, #f4f4f5);
+  }
+
+  &:focus-visible {
+    outline: 2px solid var(--primary-color, #2f6e5d);
+    outline-offset: 2px;
+  }
+}
+
+.app-dialog-panel__body {
+  padding: var(--space-lg, 1.5rem);
+}
+
+@keyframes app-dialog-fade-in {
+  from {
+    opacity: 0;
+  }
+  to {
+    opacity: 1;
+  }
+}
+
+@keyframes app-dialog-scale-in {
+  from {
+    opacity: 0;
+    transform: scale(0.96);
+  }
+  to {
+    opacity: 1;
+    transform: scale(1);
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .app-dialog-backdrop,
+  .app-dialog-panel {
+    animation: none;
+  }
+}

src/app/shared/ui/dialog/dialog.component.ts

@@ -0,0 +1,107 @@
+import {
+  AfterViewInit,
+  ChangeDetectionStrategy,
+  Component,
+  ElementRef,
+  HostListener,
+  input,
+  OnChanges,
+  output,
+  SimpleChanges,
+  ViewChild
+} from '@angular/core';
+
+export type DialogSize = 'sm' | 'md' | 'lg';
+
+const FOCUSABLE_SELECTOR =
+  'a[href], button:not([disabled]), textarea:not([disabled]), input:not([disabled]), select:not([disabled]), [tabindex]:not([tabindex="-1"])';
+
+@Component({
+  selector: 'app-dialog',
+  standalone: true,
+  templateUrl: './dialog.component.html',
+  styleUrl: './dialog.component.scss',
+  changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class DialogComponent implements OnChanges, AfterViewInit {
+  readonly open = input(false);
+  readonly titleText = input<string | null>(null);
+  readonly size = input<DialogSize>('md');
+
+  readonly closed = output<void>();
+
+  @ViewChild('panel') private panelRef?: ElementRef<HTMLElement>;
+
+  private previouslyFocused: HTMLElement | null = null;
+
+  ngOnChanges(changes: SimpleChanges): void {
+    if (changes['open']) {
+      if (this.open()) {
+        this.previouslyFocused = document.activeElement as HTMLElement | null;
+        queueMicrotask(() => this.focusPanel());
+      } else {
+        this.previouslyFocused?.focus();
+        this.previouslyFocused = null;
+      }
+    }
+  }
+
+  ngAfterViewInit(): void {
+    if (this.open()) {
+      this.focusPanel();
+    }
+  }
+
+  @HostListener('document:keydown', ['$event'])
+  protected handleKeydown(event: KeyboardEvent): void {
+    if (!this.open()) {
+      return;
+    }
+    if (event.key === 'Escape') {
+      this.requestClose();
+      return;
+    }
+    if (event.key === 'Tab') {
+      this.trapFocus(event);
+    }
+  }
+
+  protected requestClose(): void {
+    this.closed.emit();
+  }
+
+  protected handleBackdropClick(): void {
+    this.requestClose();
+  }
+
+  private focusPanel(): void {
+    const panel = this.panelRef?.nativeElement;
+    if (!panel) {
+      return;
+    }
+    const focusable = panel.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR);
+    (focusable[0] ?? panel).focus();
+  }
+
+  private trapFocus(event: KeyboardEvent): void {
+    const panel = this.panelRef?.nativeElement;
+    if (!panel) {
+      return;
+    }
+    const focusable = Array.from(panel.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR));
+    if (focusable.length === 0) {
+      return;
+    }
+    const first = focusable[0];
+    const last = focusable[focusable.length - 1];
+    const active = document.activeElement;
+
+    if (event.shiftKey && active === first) {
+      event.preventDefault();
+      last.focus();
+    } else if (!event.shiftKey && active === last) {
+      event.preventDefault();
+      first.focus();
+    }
+  }
+}