## Summary
PR 1 of 3 from the user-menu / profile / cross-app-link chantier per the agreed staging:
| PR | Périmètre |
| --- | --- |
| **PR 1 (this one)** | Shared `UserMenu` dropdown component + integration on `portal-shell` and `portal-admin`; anonymous Sign-in button moves to `rounded-md`. |
| PR 2 | `/profile` pages on both apps. |
| PR 3 | `/api/me/capabilities` endpoint + real role surfacing on the sidebar widget + cross-app links in the menu (both directions). |
Lands the gitea / github-shaped avatar dropdown so admins and end users get the familiar "Signed in as / Profile / Settings / Sign out" pattern. Future entries (cross-app link, role-based visibility) plug into the same `items` input without touching the shared component.
## What lands
### Shared component — [`libs/shared/ui/src/lib/user-menu/`](libs/shared/ui/src/lib/user-menu/)
```html
<lib-user-menu
[displayName]="state.user.displayName"
[username]="state.user.username"
[initials]="initials()"
[items]="userMenuItems"
[signedInAsLabel]="…"
[signOutLabel]="…"
[triggerAriaLabel]="…"
(signOut)="signOut()"
/>
```
- Avatar trigger (initials in a rounded square + chevron-down hint), CDK `cdkMenuTriggerFor` opening the panel in an overlay portal. Same primitives `ThemeSwitcher` and `LocaleSwitcher` already use — keyboard nav, focus management and Escape-to-close come for free.
- Panel layout: "Signed in as" small-caps header → `displayName` → `username` → separator → caller-supplied `items` → separator → dedicated Sign out row at the bottom.
- `UserMenuItem` shape supports `routerLink` (intra-app) **and** `href` (cross-app / external) so PR 3's "Open Portal Admin" entry can land without re-shaping the API.
- Disabled items render as `aria-disabled` rows with a right-aligned badge — same Soon-chip pattern the admin sidebar already uses for not-yet-shipped entries.
- Sign out is **not** an item — it's a hardcoded row that emits a `signOut` output. Avoids special-casing item types and keeps the destructive action visually + structurally distinct.
- Avatar background is driven by `--user-menu-avatar-bg` / `--user-menu-avatar-fg` CSS custom properties so each host header can re-skin without forking the component (portal-admin uses translucent white over the brand-primary-600 header; portal-shell keeps the default brand-primary-500).
### Portal-shell integration — [`apps/portal-shell/src/app/components/header/`](apps/portal-shell/src/app/components/header/)
- Authenticated state in [header.html](apps/portal-shell/src/app/components/header/header.html) swaps the inline avatar + display name + Sign-out button for `<lib-user-menu>`.
- Anonymous Sign-in button moves from `rounded-full` → `rounded-md` per the reference image. Loading + error chips follow for visual consistency with the new square-ish avatar.
- 6 new strings in [`messages.fr.xlf`](apps/portal-shell/src/locale/messages.fr.xlf): `header.userMenu.{profile,settings,signedInAs,signOut,trigger.aria}` + `common.badge.soon`.
### Portal-admin integration — [`apps/portal-admin/src/app/components/header/`](apps/portal-admin/src/app/components/header/)
- Same swap, leaner: the admin header keeps its inline `.btn--primary` / `.btn--secondary` for anonymous + error states (no search bar / notification cluster, per ADR-0020), only the authenticated state goes through the menu.
- Overrides `--user-menu-avatar-bg` / `--user-menu-avatar-fg` in [`header.scss`](apps/portal-admin/src/app/components/header/header.scss) under `.auth-widget lib-user-menu` so the avatar reads on the brand-primary-600 background. No FR labels (no admin locale in v1 per ADR-0020).
## Notes for the reviewer
- **Why `Sign out` outside the `items` array?** It's the only destructive action in the panel + always present + emits an event rather than navigates. Keeping it special-cased lets the `items` API stay tight (`{ label, icon?, routerLink? | href?, disabled?, badge? }`) and gives each app a single typed entry point (`signOut` output) rather than a brittle `items[].action === 'sign-out'` discriminator.
- **Why `data-testid="user-menu"` on the component host?** The shared spec already covers panel internals; each app's spec needs a top-level handle to reach the trigger without coupling to the avatar CSS class. Same pattern as the existing `data-testid="sign-in-button"`.
- **Profile entry points at `/profile` on both apps in this PR.** Portal-shell already has a demo `/profile` route, so the link works; portal-admin will 404 until PR 2 lands the actual page. Interim cost is acceptable given PR 2 lands directly behind this.
- **No ADR for the component.** It's a UI primitive in `libs/shared/ui` — same tier as `Icon`. Promotion criteria, dark-mode, a11y, and i18n all follow the existing ADRs already in force (ADR-0004 + 0016 + 0019).
## Test plan
- [x] `pnpm nx test shared-ui` — **8 specs pass** (was 3, +5 for `UserMenu`).
- [x] `pnpm nx test portal-shell` — **35 specs pass** (was 34, +1 for the new "opens menu" assertion).
- [x] `pnpm nx test portal-admin` — **46 specs pass** (was 45, +1 for the new "opens menu" assertion).
- [x] `pnpm nx run-many -t lint test build --projects=portal-shell,portal-admin,shared-ui,shared-state,feature-auth` — 15/15 tasks green, including the i18n-strict `portal-shell:build:production`.
- [ ] Manual smoke — sign in on portal-shell, confirm the avatar lives at the top right with the dropdown opening on click / Enter / ArrowDown, Profile navigates to `/profile`, Settings appears greyed with a "Soon" badge, Sign out triggers the BFF logout. Repeat on portal-admin (the avatar background should pick the translucent-white override over the brand-primary-600 header).
## What's next
PR 2 picks up directly: builds a real `/profile` page on each app, both reading from `feature-auth`'s `currentUser()` signal.
---------
Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #149
julien
a8ead65ea8