refactor(client-portal) : remove client portal feature entirely

- drop ClientPortal module, ClientTicket entity, ROLE_CLIENT and all couplings (Task, TaskDocument, User, Notification) back to an internal-only model

- migration drops client_ticket / user_allowed_projects / related FK columns and removes leftover external client accounts (would otherwise be promoted to ROLE_USER)

- remove client-portal frontend module, admin tickets tab, user portal section, portal nav item and portal/clientTicket i18n keys

- fix directory nav icon (invalid mdi:contact-multiple-outline -> mdi:card-account-details-outline)

- add 'make sync-permissions' target, wire it into install/db-reset and the prod deploy script

config/packages/security.yaml

@@ -1,6 +1,6 @@
 security:
     role_hierarchy:
-        ROLE_ADMIN: [ROLE_USER, ROLE_CLIENT]
+        ROLE_ADMIN: [ROLE_USER]
 
     # https://symfony.com/doc/current/security.html#registering-the-user-hashing-passwords
     password_hashers: