feat(server/auth): switch user identity to phone with email optional

Phone becomes the required, unique login identifier; email and name turn
optional. Login now accepts either via a single identifier field, refresh
re-checks tenant membership, and the dev seed provides phone numbers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/repository/queries/auth.sql

@@ -3,6 +3,12 @@ SELECT id, email, phone, password_hash, name, avatar_url, status, created_at, up
 FROM users
 WHERE email = sqlc.arg(email) AND deleted_at IS NULL;
 
+-- name: GetUserByLoginIdentifier :one
+SELECT id, email, phone, password_hash, name, avatar_url, status, created_at, updated_at
+FROM users
+WHERE (email = sqlc.arg(login_identifier) OR phone = sqlc.arg(login_identifier))
+  AND deleted_at IS NULL;
+
 -- name: GetUserByID :one
 SELECT id, email, phone, password_hash, name, avatar_url, status, created_at, updated_at
 FROM users