Add access control rework

toju-app/src/app/domains/access-control/README.md

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+# Access Control Domain
+
+Role and permission rules for servers, including default system roles, role assignment normalization, permission resolution, legacy compatibility mapping, and room-level access-control hydration.
+
+## Module map
+
+```
+access-control/
+├── domain/
+│   ├── access-control.models.ts            MemberIdentity and RoomPermissionDefinition domain types
+│   ├── access-control.constants.ts         SYSTEM_ROLE_IDS and permission metadata
+│   ├── role.rules.ts                       Role defaults, normalization, ordering, create/update helpers
+│   ├── role-assignment.rules.ts            Assignment normalization and member-role lookups
+│   ├── permission.rules.ts                 Permission resolution and moderation hierarchy checks
+│   ├── room.rules.ts                       Legacy compatibility, room hydration, room-level normalization
+│   └── access-control.logic.ts             Public barrel for domain rules
+│
+└── index.ts                                Domain barrel used by other layers
+```
+
+## Domain rules
+
+| Function                                                        | Purpose                                                                                                       |
+| --------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- |
+| `normalizeRoomRoles(room.roles, room.permissions)`              | Repairs missing/default roles and keeps role ordering stable                                                  |
+| `normalizeRoomRoleAssignments(...)`                             | Deduplicates and backfills member role assignments from legacy member role fields                             |
+| `normalizeChannelPermissionOverrides(...)`                      | Deduplicates valid channel overrides and drops invalid references                                             |
+| `resolveRoomPermission(room, identity, permission, channelId?)` | Resolves effective permission state including overrides                                                       |
+| `canManageMember(...)`                                          | Applies both permission checks and role hierarchy checks                                                      |
+| `canManageRole(...)`                                            | Prevents editing roles at or above the actor's highest role                                                   |
+| `normalizeRoomAccessControl(room)`                              | Produces a fully hydrated room with normalized roles, assignments, overrides, and legacy compatibility fields |
+
+## Layering
+
+- Domain rules stay pure and only depend on `shared-kernel` contracts plus other files in this domain.
+- Renderer shells and NgRx effects should keep importing from `src/app/domains/access-control/` instead of internal files.
+- Legacy `room.permissions` booleans remain compatibility output only; normalized data lives on `roles`, `roleAssignments`, `channelPermissions`, and `slowModeInterval`.