chore(migrations): renumber 014/015/016 -> 015/016/017 to avoid collision with master 014_card_files

backend/migrations/015_notifications.sql

@@ -0,0 +1,42 @@
+-- Per-user notifications + persisted @mentions.
+-- Created by card chat messages (card_messages).
+--
+-- Kinds:
+--   mention       — user mentioned via @username in body
+--   assigned_chat — user is the card's assignee and someone else commented
+--   reply         — user previously commented on this card (or is requester)
+-- A row is created per (recipient_user, message). The kind chosen is the
+-- highest priority among those that apply: mention > assigned_chat > reply.
+
+CREATE TABLE IF NOT EXISTS notifications (
+    id          TEXT PRIMARY KEY,
+    user_id     TEXT NOT NULL,
+    card_id     TEXT NOT NULL,
+    message_id  TEXT NOT NULL,
+    kind        TEXT NOT NULL,
+    actor_id    TEXT NOT NULL,
+    created_at  TEXT NOT NULL,
+    read_at     TEXT,
+    FOREIGN KEY (card_id)    REFERENCES cards(id)         ON DELETE CASCADE,
+    FOREIGN KEY (message_id) REFERENCES card_messages(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_notifications_user_unread
+    ON notifications(user_id, read_at, created_at DESC);
+
+CREATE INDEX IF NOT EXISTS idx_notifications_user_created
+    ON notifications(user_id, created_at DESC);
+
+CREATE TABLE IF NOT EXISTS card_mentions (
+    id          TEXT PRIMARY KEY,
+    card_id     TEXT NOT NULL,
+    message_id  TEXT NOT NULL,
+    user_id     TEXT NOT NULL,
+    created_at  TEXT NOT NULL,
+    FOREIGN KEY (card_id)    REFERENCES cards(id)         ON DELETE CASCADE,
+    FOREIGN KEY (message_id) REFERENCES card_messages(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_card_mentions_user    ON card_mentions(user_id, created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_card_mentions_card    ON card_mentions(card_id);
+CREATE INDEX IF NOT EXISTS idx_card_mentions_message ON card_mentions(message_id);