Adopt sqlc for typed Postgres queries behind store entities.

db/queries/users.sql

@@ -0,0 +1,43 @@
+-- name: CreateUser :exec
+INSERT INTO users (id, username, name, password_hash, role, avatar_url, state, created_at)
+VALUES ($1, $2, $3, $4, $5, '', '', $6);
+
+-- name: GetUserByID :one
+SELECT id, username, name, role, avatar_url, state, created_at
+FROM users
+WHERE id = $1;
+
+-- name: GetUserByUsername :one
+SELECT id, username, name, role, avatar_url, state, created_at, password_hash
+FROM users
+WHERE username = $1;
+
+-- name: ListUsers :many
+SELECT id, username, name, role, avatar_url, state, created_at
+FROM users
+ORDER BY created_at ASC;
+
+-- name: CountAdmins :one
+SELECT COUNT(*)::bigint AS count
+FROM users
+WHERE role = $1;
+
+-- name: GetUserRole :one
+SELECT role
+FROM users
+WHERE id = $1;
+
+-- name: UpdateUserRole :execresult
+UPDATE users
+SET role = $1
+WHERE id = $2;
+
+-- name: UpdateUserState :exec
+UPDATE users
+SET state = $1
+WHERE id = $2;
+
+-- name: UpdateUserStateAndAvatar :exec
+UPDATE users
+SET state = $1, avatar_url = $2
+WHERE id = $3;