Whisper 0.1.0: private messages between players

/pm (/w) with names, #userid, SteamIDs, @me, @aim, @random, @randomt and
@randomct, /r to reply, and /block, /blocklist, /unblock. Lines use
CS2-Tags' rank prefixes and colours: >[[M] Kalus -> me] message. Gagged
players can't send; blocks stop everyone but staff. Messages are kept in
CS2-SimpleAdmin's database while History is on (css_whisper_history).

Migrations/001_CreateTables.sql

@@ -0,0 +1,40 @@
+-- Whisper's tables, in CS2-SimpleAdmin's database. Applied once at load, tracked in wh_migrations.
+-- All times are UTC.
+
+-- One row per private message attempt, sent or not (while History is on in Whisper.json).
+-- result: sent, blocked, gagged, cooldown, no_target, ambiguous, group_target, too_long.
+-- The recipient columns are NULL when no single player was found. team: 0 none, 1 spectator,
+-- 2 T, 3 CT. alive: 1 when on T/CT with a living pawn. target is what the sender typed for it.
+CREATE TABLE IF NOT EXISTS `wh_messages` (
+    `id` bigint unsigned NOT NULL AUTO_INCREMENT,
+    `message_key` char(32) NOT NULL,
+    `sent_at` datetime NOT NULL,
+    `server_id` int NULL,
+    `map` varchar(64) NOT NULL,
+    `sender_steamid64` bigint unsigned NOT NULL,
+    `sender_name` varchar(128) NOT NULL,
+    `sender_team` tinyint NOT NULL,
+    `sender_alive` tinyint NOT NULL,
+    `recipient_steamid64` bigint unsigned NULL,
+    `recipient_name` varchar(128) NULL,
+    `recipient_team` tinyint NULL,
+    `recipient_alive` tinyint NULL,
+    `target` varchar(128) NOT NULL,
+    `message` varchar(512) NOT NULL,
+    `result` varchar(16) NOT NULL,
+    PRIMARY KEY (`id`),
+    UNIQUE KEY `uq_message_key` (`message_key`),
+    KEY `ix_sent_at` (`sent_at`),
+    KEY `ix_sender` (`sender_steamid64`, `sent_at`),
+    KEY `ix_recipient` (`recipient_steamid64`, `sent_at`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
+
+-- Who each player has blocked from messaging them (/block). blocked_name is their name when blocked,
+-- empty when blocked by SteamID64 while offline.
+CREATE TABLE IF NOT EXISTS `wh_blocks` (
+    `blocker_steamid64` bigint unsigned NOT NULL,
+    `blocked_steamid64` bigint unsigned NOT NULL,
+    `blocked_name` varchar(128) NOT NULL DEFAULT '',
+    `created_at` datetime NOT NULL,
+    PRIMARY KEY (`blocker_steamid64`, `blocked_steamid64`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;