feat(portal-shell): align header logo zone with the sidebar rail (#85)

## Summary

- Split the header into two zones: a **logo zone** whose width tracks the sidebar (16 rem expanded / 4 rem collapsed), and the existing search + actions cluster on the right.
- The logo glyph stays at both widths; the "APF Portal" wordmark hides when the rail collapses, mirroring the sidebar's icon-only mode.
- Promote the sidebar's `collapsed` state to a new [`LayoutStateService`](apps/portal-shell/src/app/state/layout-state.service.ts) (Signals + `localStorage`) so header and sidebar share a single source of truth.

## Why a service rather than prop-drilling

Two reasons:

1. The state is **shell-level**, not sidebar-internal — the header now reads it, and future surfaces (right rail, breadcrumbs, command palette) will too. Passing it down via inputs would force `<app-root>` to act as the owner and turn every intermediate component into a relay.
2. As we add other cross-cutting shell state (density, theme, panel pinning, RTL), they all belong in the same place. `LayoutStateService` is the natural collector and stays trivial as long as we don't over-broaden it. v1 ships with one signal — keeping it narrow.

The service is `providedIn: 'root'` (singleton), Signals-only, and owns localStorage persistence — same UX as before, just relocated.

## Decisions worth flagging

- **Widths stay duplicated between `header.scss` and `sidebar.scss`** (16 rem / 4 rem). Extracting a shared SCSS variable would be premature — only two callers, and the coupling is loud (cross-file comment in `header.scss`). If a third surface needs the same widths, we promote to a shared token.
- **Border continuity.** The logo zone's right border and the sidebar's right border share the same x coordinate, so they read as one continuous vertical separator running the full shell height. Same `#e5e7eb` so the seam is invisible.
- **Width transition** matches the sidebar's (`0.18s ease-out`) and is skipped under `prefers-reduced-motion: reduce`.
- **Sidebar component lost its private state.** Its own signal + effect + storage glue is gone; it delegates reads to the service and the toggle click to `layout.toggleSidebar()`. Net `sidebar.ts` shrunk by ~15 lines.

## Test plan

- [x] `pnpm exec nx run-many -t lint test build --projects=portal-shell` — green (25 / 25 specs, +6 for the new service spec + header zone tests).
- [x] Production build under bundle budgets (100 kB gzip initial — +0.2 kB vs main).
- [ ] Manual: load `/`, confirm the logo zone's right edge aligns exactly with the sidebar's right edge at both widths.
- [ ] Manual: toggle the sidebar → both columns animate in sync; wordmark hides; logo glyph stays centered in the 4 rem zone.
- [ ] Manual: reload after toggling → both header and sidebar restore to the persisted state.
- [ ] Manual: `prefers-reduced-motion: reduce` → no width animation in either zone.

---------

Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #85

apps/portal-shell/src/app/components/header/header.html

@@ -1,7 +1,9 @@
-<header class="flex h-16 items-center gap-4 border-b border-gray-200 bg-white px-4 sm:px-6">
+<header class="flex h-16 items-center border-b border-gray-200 bg-white">
+  <div class="header__logo-zone" [class.header__logo-zone--collapsed]="collapsed()">
     <a
       routerLink="/"
-    class="flex shrink-0 items-center gap-3 rounded-md text-brand-primary-500 transition-colors hover:text-brand-primary-600 focus-visible:outline-2 focus-visible:outline-offset-4 focus-visible:outline-brand-primary-500"
+      class="flex h-full items-center gap-3 rounded-md text-brand-primary-500 transition-colors hover:text-brand-primary-600 focus-visible:outline-2 focus-visible:outline-offset-4 focus-visible:outline-brand-primary-500"
+      [class.justify-center]="collapsed()"
     >
       <img
         src="logos/apf-portal.svg"
@@ -9,11 +11,15 @@
         aria-hidden="true"
         width="36"
         height="36"
-      class="h-9 w-9"
+        class="h-9 w-9 shrink-0"
       />
+      @if (!collapsed()) {
       <span class="text-base font-semibold sm:text-lg">APF Portal</span>
+      }
     </a>
+  </div>
 
+  <div class="flex flex-1 items-center gap-4 px-4 sm:px-6">
     <form role="search" class="mx-2 hidden flex-1 md:flex" (submit)="$event.preventDefault()">
       <label class="sr-only" for="global-search">Search the portal</label>
       <div
@@ -62,4 +68,5 @@
         ?
       </span>
     </nav>
+  </div>
 </header>

apps/portal-shell/src/app/components/header/header.scss

@@ -0,0 +1,29 @@
+// Logo zone widths kept in lock-step with `sidebar.scss` (16rem
+// expanded / 4rem collapsed). When the sidebar toggles, the rail
+// below this zone reaches exactly the same boundary, so the brand
+// stays flush with the navigation column. If those widths ever
+// change, update both files together — extracting a shared SCSS
+// variable would be the right move only if a third surface needs the
+// same coupling.
+.header__logo-zone {
+  display: flex;
+  align-items: center;
+  flex-shrink: 0;
+  width: 16rem;
+  height: 100%;
+  padding: 0 0.75rem;
+  border-right: 1px solid #e5e7eb;
+  transition: width 0.18s ease-out;
+
+  &--collapsed {
+    width: 4rem;
+    padding: 0 0.5rem;
+    justify-content: center;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .header__logo-zone {
+    transition: none;
+  }
+}

apps/portal-shell/src/app/components/header/header.spec.ts

@@ -1,9 +1,11 @@
 import { TestBed } from '@angular/core/testing';
 import { provideRouter } from '@angular/router';
 import { Header } from './header';
+import { LayoutStateService } from '../../state/layout-state.service';
 
 describe('Header', () => {
   beforeEach(async () => {
+    localStorage.clear();
     await TestBed.configureTestingModule({
       imports: [Header],
       providers: [provideRouter([])],
@@ -45,4 +47,29 @@ describe('Header', () => {
     expect(root.querySelector('button[aria-label="Help"]')).not.toBeNull();
     expect(root.querySelector('button[aria-label="Settings"]')).not.toBeNull();
   });
+
+  it('renders the logo zone, expanded with wordmark by default', async () => {
+    const fixture = TestBed.createComponent(Header);
+    fixture.detectChanges();
+    await fixture.whenStable();
+    const root = fixture.nativeElement as HTMLElement;
+    const zone = root.querySelector('.header__logo-zone');
+    expect(zone).not.toBeNull();
+    expect(zone?.classList.contains('header__logo-zone--collapsed')).toBe(false);
+    expect(root.textContent ?? '').toContain('APF Portal');
+  });
+
+  it('collapses the logo zone and hides the wordmark when the sidebar is collapsed', async () => {
+    const layout = TestBed.inject(LayoutStateService);
+    layout.setSidebarCollapsed(true);
+
+    const fixture = TestBed.createComponent(Header);
+    fixture.detectChanges();
+    await fixture.whenStable();
+    const root = fixture.nativeElement as HTMLElement;
+    const zone = root.querySelector('.header__logo-zone');
+    expect(zone?.classList.contains('header__logo-zone--collapsed')).toBe(true);
+    const wordmark = root.querySelector('a[href="/"] span');
+    expect(wordmark).toBeNull();
+  });
 });

apps/portal-shell/src/app/components/header/header.ts

@@ -1,12 +1,17 @@
-import { ChangeDetectionStrategy, Component } from '@angular/core';
+import { ChangeDetectionStrategy, Component, inject } from '@angular/core';
 import { RouterLink } from '@angular/router';
 import { Icon } from '../icon/icon';
+import { LayoutStateService } from '../../state/layout-state.service';
 
 /**
  * Top-of-page banner.
  *
  * v1 layout (left → right):
- *   - Brand: APF logo + portal name, linking to "/".
+ *   - Logo zone — sized to the sidebar rail so the brand sits flush
+ *     above the navigation column. When the sidebar collapses, the
+ *     logo zone shrinks too and the wordmark hides, leaving just the
+ *     glyph centered above the icon-only rail. Driven by
+ *     `LayoutStateService`.
  *   - Global search input (placeholder; wired to a real search service
  *     once we have content to query).
  *   - Action cluster: notifications, help, settings, and an avatar
@@ -20,6 +25,11 @@ import { Icon } from '../icon/icon';
   selector: 'app-header',
   imports: [RouterLink, Icon],
   templateUrl: './header.html',
+  styleUrl: './header.scss',
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class Header {}
+export class Header {
+  private readonly layout = inject(LayoutStateService);
+
+  protected readonly collapsed = this.layout.sidebarCollapsed;
+}

apps/portal-shell/src/app/components/sidebar/sidebar.ts

@@ -1,6 +1,7 @@
-import { ChangeDetectionStrategy, Component, effect, signal } from '@angular/core';
+import { ChangeDetectionStrategy, Component, inject } from '@angular/core';
 import { RouterLink, RouterLinkActive } from '@angular/router';
 import { Icon, type IconName } from '../icon/icon';
+import { LayoutStateService } from '../../state/layout-state.service';
 
 /**
  * Primary side navigation.
@@ -10,8 +11,9 @@ import { Icon, type IconName } from '../icon/icon';
  *   - collapsed: icon-only. ~64 px wide. Group titles hide; labels
  *     remain in the accessible name of each link via `aria-label`.
  *
- * The collapsed state is owned here and persisted in `localStorage`
+ * The collapsed state is owned by `LayoutStateService` (shell-level
- * so a user's preference survives reloads (zero backend roundtrip).
+ * shared state) so the header's logo zone can size itself to match
+ * the sidebar rail.
  *
  * v1 menu is static and points to `#` placeholders — the live routes
  * land alongside the auth flow (ADR-0009). The shape is already
@@ -60,8 +62,6 @@ const MENU: readonly MenuGroup[] = [
   },
 ];
 
-const STORAGE_KEY = 'portal-shell:sidebar-collapsed';
-
 @Component({
   selector: 'app-sidebar',
   imports: [RouterLink, RouterLinkActive, Icon],
@@ -70,30 +70,12 @@ const STORAGE_KEY = 'portal-shell:sidebar-collapsed';
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class Sidebar {
-  protected readonly menu = MENU;
+  private readonly layout = inject(LayoutStateService);
-  protected readonly collapsed = signal(readPersistedCollapsed());
 
-  constructor() {
+  protected readonly menu = MENU;
-    effect(() => {
+  protected readonly collapsed = this.layout.sidebarCollapsed;
-      const value = this.collapsed();
-      try {
-        localStorage.setItem(STORAGE_KEY, value ? '1' : '0');
-      } catch {
-        // localStorage can throw in private-mode contexts; the
-        // sidebar still works, the preference just doesn't persist.
-      }
-    });
-  }
 
   protected toggle(): void {
-    this.collapsed.update((v) => !v);
+    this.layout.toggleSidebar();
-  }
-}
-
-function readPersistedCollapsed(): boolean {
-  try {
-    return localStorage.getItem(STORAGE_KEY) === '1';
-  } catch {
-    return false;
   }
 }

apps/portal-shell/src/app/state/layout-state.service.spec.ts

@@ -0,0 +1,43 @@
+import { TestBed } from '@angular/core/testing';
+import { LayoutStateService } from './layout-state.service';
+
+describe('LayoutStateService', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    TestBed.resetTestingModule();
+  });
+
+  it('defaults to expanded when no preference is persisted', () => {
+    const service = TestBed.inject(LayoutStateService);
+    expect(service.sidebarCollapsed()).toBe(false);
+  });
+
+  it('initialises from the persisted preference', () => {
+    localStorage.setItem('portal-shell:sidebar-collapsed', '1');
+    const service = TestBed.inject(LayoutStateService);
+    expect(service.sidebarCollapsed()).toBe(true);
+  });
+
+  it('toggleSidebar flips the value and persists it', () => {
+    const service = TestBed.inject(LayoutStateService);
+    expect(service.sidebarCollapsed()).toBe(false);
+
+    service.toggleSidebar();
+    expect(service.sidebarCollapsed()).toBe(true);
+    TestBed.tick();
+    expect(localStorage.getItem('portal-shell:sidebar-collapsed')).toBe('1');
+
+    service.toggleSidebar();
+    expect(service.sidebarCollapsed()).toBe(false);
+    TestBed.tick();
+    expect(localStorage.getItem('portal-shell:sidebar-collapsed')).toBe('0');
+  });
+
+  it('setSidebarCollapsed writes the explicit value', () => {
+    const service = TestBed.inject(LayoutStateService);
+    service.setSidebarCollapsed(true);
+    expect(service.sidebarCollapsed()).toBe(true);
+    TestBed.tick();
+    expect(localStorage.getItem('portal-shell:sidebar-collapsed')).toBe('1');
+  });
+});

apps/portal-shell/src/app/state/layout-state.service.ts

@@ -0,0 +1,53 @@
+import { Injectable, effect, signal } from '@angular/core';
+
+/**
+ * Shell-level layout state shared by the header and the sidebar.
+ *
+ * Currently a single piece of state: whether the sidebar is collapsed
+ * to its icon-only rail. The collapsed state is persisted in
+ * `localStorage` so it survives reloads without a backend round-trip.
+ *
+ * Lives outside of `<app-sidebar>` so that `<app-header>` can also
+ * read it — that's what lets the header's logo zone size itself to
+ * match the sidebar width, and stay perfectly aligned with the rail
+ * below it. As more cross-cutting shell state lands (density, theme,
+ * panel pinning, …), it joins here rather than spreading across
+ * sibling components.
+ */
+
+const STORAGE_KEY = 'portal-shell:sidebar-collapsed';
+
+@Injectable({ providedIn: 'root' })
+export class LayoutStateService {
+  private readonly _sidebarCollapsed = signal(readPersistedCollapsed());
+
+  readonly sidebarCollapsed = this._sidebarCollapsed.asReadonly();
+
+  constructor() {
+    effect(() => {
+      const value = this._sidebarCollapsed();
+      try {
+        localStorage.setItem(STORAGE_KEY, value ? '1' : '0');
+      } catch {
+        // localStorage can throw in private-mode contexts; the UI
+        // still works, the preference just doesn't persist.
+      }
+    });
+  }
+
+  toggleSidebar(): void {
+    this._sidebarCollapsed.update((v) => !v);
+  }
+
+  setSidebarCollapsed(value: boolean): void {
+    this._sidebarCollapsed.set(value);
+  }
+}
+
+function readPersistedCollapsed(): boolean {
+  try {
+    return localStorage.getItem(STORAGE_KEY) === '1';
+  } catch {
+    return false;
+  }
+}