- remove unused AuthReader::invitation_mode and ReferralAttribution
helpers (get_or_create_code / validate_ref); contract test now
asserts the canonical invit_code_s reader in CreditsRuntime
- drop legacy aksrt_invite table from uninstall cleanup list
- track referral code creation time (aksrt_referral_code_created)
and surface it in the referral ops REST list
- formalize ops list headers (归属用户/推广码/启用状态/推广用户数/
有效付费用户数/创建时间) and right-align count columns