feat: use modals for creation, side panels for editing

- Team page: add member via modal with password confirmation,
  keep SlidePanel for editing existing members only
- Settings: add role via modal with color picker presets,
  keep inline editing for existing roles
- Remove create-mode code from TeamMemberPanel
- Add i18n keys: confirmPassword, passwordsDoNotMatch, memberAdded,
  roleColor (en + ar)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src/i18n/en.json

@@ -209,6 +209,7 @@
   "team.title": "Team",
   "team.members": "Team Members",
   "team.addMember": "Add Member",
+  "team.memberAdded": "Member added successfully",
   "team.newMember": "New Team Member",
   "team.editMember": "Edit Team Member",
   "team.myProfile": "My Profile",
@@ -231,6 +232,8 @@
   "team.membersPlural": "team members",
   "team.fullName": "Full name",
   "team.defaultPassword": "Default: changeme123",
+  "team.confirmPassword": "Confirm Password",
+  "team.passwordsDoNotMatch": "Passwords do not match",
   "team.optional": "(optional)",
   "team.fixedRole": "Fixed role for managers",
   "team.remove": "Remove",
@@ -673,6 +676,7 @@
   "settings.rolesDesc": "Define job roles like Designer, Strategist, etc. These are assigned to team members separately from permission levels.",
   "settings.addRole": "Add Role",
   "settings.roleName": "Role name",
+  "settings.roleColor": "Color",
   "settings.deleteRoleConfirm": "Are you sure you want to delete this role?",
   "settings.noRoles": "No roles defined yet. Add your first role."
 }