Wrap startup setting names only at underscores

[SaladDay]

Settings → Service and deployment → Startup settings split variable names mid-word on phones (OAC_EXECUTIO N_CONCURRE NCY), because the shared .system-code style sets overflow-wrap: anywhere and the table shrinks the name column to that minimum. The names now break only at the existing <wbr> after each underscore; desktop is unchanged and the page has no horizontal overflow at 390 px.

Checks: pnpm --filter @oac/web typecheck; fixture console screenshots at 390 px (zh, en) and 1440 px (zh).

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