The bot + MCP only know Linear (LinearTaskSystem / DualWriteTaskSystem); there is no Postgres-native TaskSystem, so Linear can't be turned off. Implement PostgresTaskSystem implements TaskSystem backed by the mirror DB: list teams/users/projects/labels/states, findByRef, searchTasks (ilike or tsvector), createTask/updateTask/comment with local TEAM-N identifier generation. Read queries already exist in tesks-ui; write logic exists in MirrorService / native-issue creation — mostly porting Kysely SQL to JdbcTemplate. This is the one true blocker for ejection.