add packaging reminder to eslint conf (#7565)

Author: simon-id

eslint.config.mjs

@@ -1,3 +1,7 @@
+// TODO: once we've well iterated on this file (6 months+),
+// we can plan to move it to its own package to reuse elsewhere.
+// written on 2026-02-12
+
 import { readFileSync } from 'fs'
 import eslintPluginJs from '@eslint/js'
 import eslintPluginStylistic from '@stylistic/eslint-plugin'