feat(api): /sessions filters by type and paginates by cursor

db/postgres/migrations/0001_init.up.sql

@@ -459,6 +459,7 @@ CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active ON bot_sessions(bot_id, d
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_parent ON bot_sessions(parent_session_id) WHERE parent_session_id IS NOT NULL;
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_created_by_user_id ON bot_sessions(created_by_user_id) WHERE created_by_user_id IS NOT NULL;
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_created_by ON bot_sessions(bot_id, created_by_user_id, deleted_at);
+CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active_updated ON bot_sessions(bot_id, updated_at DESC, id DESC) WHERE deleted_at IS NULL;
 
 -- Add FK from routes to sessions (deferred to avoid circular dependency during CREATE).
 ALTER TABLE bot_channel_routes

db/postgres/migrations/0098_paged_sessions_index.down.sql

@@ -0,0 +1,3 @@
+-- 0098_paged_sessions_index (down)
+
+DROP INDEX IF EXISTS idx_bot_sessions_bot_active_updated;

db/postgres/migrations/0098_paged_sessions_index.up.sql

@@ -0,0 +1,9 @@
+-- 0098_paged_sessions_index
+-- Add a composite (bot_id, updated_at DESC, id DESC) partial index on
+-- non-deleted rows to back the new paged /sessions endpoint. The previous
+-- indexes covered (bot_id) and (bot_id, deleted_at) but did not help when
+-- ordering by updated_at DESC, id DESC for keyset pagination.
+
+CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active_updated
+  ON bot_sessions(bot_id, updated_at DESC, id DESC)
+  WHERE deleted_at IS NULL;

db/postgres/queries/sessions.sql

@@ -45,6 +45,46 @@ WHERE s.bot_id = sqlc.arg(bot_id)
   AND s.deleted_at IS NULL
 ORDER BY s.updated_at DESC;
 
+-- name: ListSessionsByBotPaged :many
+-- Cursor uses (updated_at, id) so pages stay stable when many rows share an
+-- updated_at. Callers always pass an explicit types filter; to opt out of
+-- filtering, pass every known type.
+SELECT
+  s.id, s.bot_id, s.route_id, s.channel_type, s.type, s.title, s.metadata,
+  s.parent_session_id, s.created_by_user_id, s.created_at, s.updated_at, s.deleted_at,
+  r.metadata AS route_metadata,
+  r.conversation_type AS route_conversation_type
+FROM bot_sessions s
+LEFT JOIN bot_channel_routes r ON r.id = s.route_id
+WHERE s.bot_id = sqlc.arg(bot_id)
+  AND s.deleted_at IS NULL
+  AND s.type = ANY(sqlc.arg(types)::text[])
+  AND (
+    NOT sqlc.arg(use_cursor)::bool
+    OR (s.updated_at, s.id) < (sqlc.arg(cursor_updated_at)::timestamptz, sqlc.arg(cursor_id)::uuid)
+  )
+ORDER BY s.updated_at DESC, s.id DESC
+LIMIT sqlc.arg(limit_count)::int;
+
+-- name: ListSessionsByBotAndCreatedByUserPaged :many
+SELECT
+  s.id, s.bot_id, s.route_id, s.channel_type, s.type, s.title, s.metadata,
+  s.parent_session_id, s.created_by_user_id, s.created_at, s.updated_at, s.deleted_at,
+  r.metadata AS route_metadata,
+  r.conversation_type AS route_conversation_type
+FROM bot_sessions s
+LEFT JOIN bot_channel_routes r ON r.id = s.route_id
+WHERE s.bot_id = sqlc.arg(bot_id)
+  AND s.created_by_user_id = sqlc.arg(created_by_user_id)
+  AND s.deleted_at IS NULL
+  AND s.type = ANY(sqlc.arg(types)::text[])
+  AND (
+    NOT sqlc.arg(use_cursor)::bool
+    OR (s.updated_at, s.id) < (sqlc.arg(cursor_updated_at)::timestamptz, sqlc.arg(cursor_id)::uuid)
+  )
+ORDER BY s.updated_at DESC, s.id DESC
+LIMIT sqlc.arg(limit_count)::int;
+
 -- name: ListSessionsByRoute :many
 SELECT *
 FROM bot_sessions

db/sqlite/migrations/0001_init.up.sql

@@ -445,6 +445,12 @@ CREATE TABLE IF NOT EXISTS bot_sessions (
   parent_session_id TEXT REFERENCES bot_sessions(id) ON DELETE SET NULL,
   created_by_user_id TEXT REFERENCES users(id) ON DELETE SET NULL,
   created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  -- updated_at is stored at second precision via CURRENT_TIMESTAMP. The
+  -- keyset cursor in `internal/db/sqlite/store/sessions_paged.go` truncates
+  -- its bound timestamp to seconds to match this storage. If we ever upgrade
+  -- this column to sub-second precision, the cursor formatter MUST keep
+  -- sub-second too so the lexicographic compare stays consistent — otherwise
+  -- rows in the same second would be skipped or returned indefinitely.
   updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
   deleted_at TEXT
 );
@@ -455,6 +461,7 @@ CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active ON bot_sessions(bot_id, d
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_parent ON bot_sessions(parent_session_id) WHERE parent_session_id IS NOT NULL;
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_created_by_user_id ON bot_sessions(created_by_user_id) WHERE created_by_user_id IS NOT NULL;
 CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_created_by ON bot_sessions(bot_id, created_by_user_id, deleted_at);
+CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active_updated ON bot_sessions(bot_id, updated_at DESC, id DESC) WHERE deleted_at IS NULL;
 
 -- bot_session_events: DCP pipeline event store for cold-start replay.
 CREATE TABLE IF NOT EXISTS bot_session_events (

db/sqlite/migrations/0023_paged_sessions_index.down.sql

@@ -0,0 +1,3 @@
+-- 0023_paged_sessions_index (down)
+
+DROP INDEX IF EXISTS idx_bot_sessions_bot_active_updated;

db/sqlite/migrations/0023_paged_sessions_index.up.sql

@@ -0,0 +1,9 @@
+-- 0023_paged_sessions_index
+-- Add a composite (bot_id, updated_at DESC, id DESC) partial index on
+-- non-deleted rows to back the new paged /sessions endpoint. The previous
+-- indexes covered (bot_id) and (bot_id, deleted_at) but did not help when
+-- ordering by updated_at DESC, id DESC for keyset pagination.
+
+CREATE INDEX IF NOT EXISTS idx_bot_sessions_bot_active_updated
+  ON bot_sessions(bot_id, updated_at DESC, id DESC)
+  WHERE deleted_at IS NULL;

db/sqlite/queries/sessions.sql

@@ -50,6 +50,14 @@ WHERE s.bot_id = sqlc.arg(bot_id)
   AND s.deleted_at IS NULL
 ORDER BY s.updated_at DESC;
 
+-- ListSessionsByBotPaged and ListSessionsByBotAndCreatedByUserPaged are not
+-- generated for SQLite. The Postgres versions live in
+-- db/postgres/queries/sessions.sql; the SQLite shim hand-rolls the query in
+-- internal/db/sqlite/store/sessions_paged.go because sqlc-sqlite cannot mix
+-- sqlc.slice with reused numbered placeholders without colliding bind indexes.
+
+
+
 -- name: ListSessionsByRoute :many
 SELECT *
 FROM bot_sessions

internal/db/model_enable_migration_test.go

@@ -157,6 +157,17 @@ CREATE TABLE model_variants (
   created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
   updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
+
+-- Minimal stub of bot_sessions so migrations targeting that table (e.g.
+-- the 0023 paged-sessions index) parse and apply against this pre-22
+-- fixture. Columns mirror only what newer migrations reference; this is
+-- not a full replica of the production schema.
+CREATE TABLE bot_sessions (
+  id TEXT PRIMARY KEY,
+  bot_id TEXT NOT NULL,
+  updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  deleted_at TEXT
+);
 `)
 	if err != nil {
 		t.Fatalf("create pre-model-enable schema: %v", err)

internal/db/sqlite/store/queries.go

@@ -4158,6 +4158,14 @@ func (q *Queries) ListSessionsByBotAndCreatedByUser(ctx context.Context, arg pgs
 	return result, nil
 }
 
+func (q *Queries) ListSessionsByBotPaged(ctx context.Context, arg pgsqlc.ListSessionsByBotPagedParams) ([]pgsqlc.ListSessionsByBotPagedRow, error) {
+	return q.listSessionsByBotPaged(ctx, arg)
+}
+
+func (q *Queries) ListSessionsByBotAndCreatedByUserPaged(ctx context.Context, arg pgsqlc.ListSessionsByBotAndCreatedByUserPagedParams) ([]pgsqlc.ListSessionsByBotAndCreatedByUserPagedRow, error) {
+	return q.listSessionsByBotAndCreatedByUserPaged(ctx, arg)
+}
+
 func (q *Queries) ListSessionsByRoute(ctx context.Context, routeID pgtype.UUID) ([]pgsqlc.BotSession, error) {
 	if q == nil || q.store == nil || q.store.queries == nil {
 		return nil, errSQLiteQueriesNotConfigured