[neeerp]

Row 205 S6: blocking accounts, from chat and from the client's /ban and /block.

• Accounts: ban_reason (Etc/BlockReason.img's number, 0 for none) and ban_until (none means for good). An ended block no longer counts (Account::blocked_at). banned, ban_msg and the new fields are skip_update, so a save of a stale account can't undo a ban.
• Login: a blocked account gets result 2 with the reason and the end as a FILETIME (build_blocked_packet). v83 reads both (HeavenClient has done so since b128) and shows BlockReason.img's text and the date, or its plain notice for reason 0. The world also refuses entry to a blocked account, whether it comes from the character select or a channel change.
• Chat commands:
  • !ban <name> [days] [reason] [note] (admin, level 3): the reason is a BlockReason.img type word or 1..=13, and leaving out the days makes the block permanent.
  • !unban <name> (admin).
  • !dc <name> (GM, level 2).
  • A block disconnects every character of the account that is online (new DirectoryMessage::Kick).
  • None of these commands works on a GM whose level is the sender's or higher.
  • Each one logs a line under gm_audit.
• Slash commands:
  • ADMIN_COMMAND 0x03 (/ban NAME) blocks for good with no reason.
  • 0x04 (/block, sent from v83's dialog: name, reason, days, note) blocks as !ban does.
  • Both reply with ADMIN_RESULT 4 0 ("You have successfully blocked access."), or 6 1 ("invalid character name") when no character has that name or the target outranks the sender. HeavenClient already shows both.
  • 0x04 with no days is ignored; the client never sends it.
• Tests:
  • Unit tests cover the packet, the parsing and the tiers.
  • The new harness test gm_ban checks a ban, the disconnect, the refused login with its reason and date, !unban, !dc, the rank check, and /ban and /block.
  • gm_commands, gm_slash, login_grade and login_to_world pass.

HeavenClient's /block dialog comes next (S6b).