perf(channels): the row menu opens and closes without re-rendering the table

The React Compiler silently skipped Channels and DataTable (a ref written
during render; the refs lint is off), and even once compiled it dropped the
memo of the rows and columns (they reach filterRows/optionsFromColumns past
the page's hooks) and the columns read the open row. Every open, close and
reposition of the right-click menu rebuilt the whole table: on "All" rows
~0.9 s to open and ~0.6 s to close (dev). Now: effect events instead of the
render-written refs, explicit memos for rows, columns and their inputs, a
module-scope keyOf, and the open row reaches its "…" through a small store.
Measured on 397 rows (dev): ~75 ms to open, ~35 ms to close.

A contract test runs the real compiler over both files and fails on any
skipped function. The dropped memos have no automated guard: they need
the full page rendered with its providers; the measurement above is the
evidence.

frontend/package.json

@@ -39,6 +39,7 @@
     "react-i18next": "^15.7.4"
   },
   "devDependencies": {
+    "@babel/core": "7.29.7",
     "@eslint/js": "9.39.1",
     "@playwright/test": "^1.61.1",
     "@tailwindcss/postcss": "^4.3.3",