Introduce `pages/api-keys/plugin.tsx` and `pages/model-routes/plugin.tsx`
defining a unified `{ key, labelId, icon, priority, danger, form,
useCreate }` contract that plugins use to contribute per-row
"configure this record" actions. The host renders one dropdown entry
per registered action and mounts each entry's form, ordered by a
single numeric priority (built-ins are ranked on the same scale; rows
flagged `danger` sink to the bottom).
Drops the older `apiKeys.rowActions` / `modelRoutes.rowActions` slots
and the implicit drawer half of
`<PluginExtraFields name="APIKeysPageGlobal" />`. The model-routes
mount point stays for the page-level quota-defaults bulk-fetch and now
also accepts a `refreshToken` so per-row saves can invalidate derived
page data without changing the row set.
