perf: sync protocol and core hardening updates

deploy/migrations/0076_album_group_reservations.up.sql

@@ -0,0 +1,17 @@
+-- sendMultiMedia 必须在解析上传媒体、逐条发送之前持久预留 grouped_id。
+-- 这张表把每个发送 random_id 固定到会话作用域内的相册组，使中途失败后
+-- 客户端只重试失败子集时仍能恢复首次整包使用的 grouped_id；intent_hash
+-- 同时阻止内容已改变的相同 random_id 借旧预留错误合并。
+CREATE TABLE album_group_reservations (
+    sender_user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    peer_type TEXT NOT NULL CHECK (peer_type IN ('user', 'channel')),
+    peer_id BIGINT NOT NULL CHECK (peer_id > 0),
+    random_id BIGINT NOT NULL CHECK (random_id <> 0),
+    intent_hash BYTEA NOT NULL CHECK (octet_length(intent_hash) = 32),
+    grouped_id BIGINT NOT NULL CHECK (grouped_id <> 0),
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    PRIMARY KEY (sender_user_id, peer_type, peer_id, random_id)
+);
+
+COMMENT ON TABLE album_group_reservations IS
+    'Durable pre-send binding from album item random_id to grouped_id; never reconstructed from a retry subset.';