feat(auth): authorization catalogues + Principal builder skeleton (ADR-0025)

Per ADR-0025's implementation phasing, lands the closed-set
catalogues + the OIDC-callback hook that composes the
session-resident Principal. No new guards yet.

- libs/shared/auth: framework-agnostic lib hosting
  authorization.types.ts (4 privileges + 24 functional roles + 6
  scope kinds + Principal type) and entra-group-to-role.ts
  (validated GUID -> slug resolver). 17 unit tests against the
  catalogues + resolver contracts.
- BFF: PrincipalBuilder composes the three axes once at sign-in;
  ScopeResolver seam (StubScopeResolver returns unrestricted in
  v1, replaced by a Prisma-backed implementation when ADR-0026's
  user_scopes table lands). 19 persona-driven tests covering the
  test tenant's full provisioning + edge cases (unknown
  privilege drift, unknown group GUID, empty permissions).
- AuthService extracts the Entra "groups" claim; AuthenticatedUser
  grows the groups: readonly string[] field.
- SessionEstablisher builds + persists the principal alongside
  the legacy user shape (additive — guards consuming user.oid
  unchanged).
- ENTRA_GROUP_MAP_PATH env var + load-entra-group-map.ts read
  the tenant-private map from infra/<env>-tenant.entra.json
  (gitignored; .example.json committed with the schema).
- ADR-0025 path references updated from libs/feature/auth
  (Angular-scoped, scope:portal-shell) to libs/shared/auth
  (consumable by both BFF and SPA).
- notes/entra-groups-claim-activation.md: operator runbook for
  the "Token configuration -> Add groups claim" step in the
  Entra admin centre.

Test plan:
- pnpm nx affected -t lint test build : 13 projects green
  (497 BFF tests + 17 shared-auth tests + 1 shared-util test +
  full lint + full build).

apps/portal-bff/.env.example

@@ -72,6 +72,18 @@ ENTRA_POST_LOGOUT_REDIRECT_URI=http://localhost:4200/
 ENTRA_ADMIN_REDIRECT_URI=http://localhost:3000/api/admin/auth/callback
 ENTRA_ADMIN_POST_LOGOUT_REDIRECT_URI=http://localhost:4300/
 
+# Authorization model (per ADR-0025). Points at the JSON file that
+# maps tenant-private Entra security-group GUIDs to the closed
+# catalogue of `apf-role-*` slugs. The BFF loads it at boot through
+# `EntraGroupToRoleResolver` (libs/shared/auth). Unset means the
+# resolver runs empty — sign-in still succeeds but every user gets
+# zero functional roles (no `apf-role-*` UI). A WARN is logged at
+# boot so an operator can spot the missing config. See
+# `infra/test-tenant.entra.example.json` for the schema; copy to
+# `infra/test-tenant.entra.json` (gitignored) and fill in the real
+# GUIDs from the Entra admin centre.
+ENTRA_GROUP_MAP_PATH=infra/test-tenant.entra.json
+
 # Cookie signing secret (per ADR-0009 §"Cookies"). Used to sign the
 # transient pre-auth cookie that carries the OIDC `state` + PKCE
 # verifier between the /auth/login redirect and the /auth/callback