feat: surface and decode the OAuth id_token in Connection Info (#2019)

When an authorization server returns an `id_token` alongside the access
token, the Inspector already persisted it and never showed it. Wire it
through to Connection Info as a viewer.

- Generalize `OAuthAccessTokenField` into `OAuthTokenField` (label + token),
  so the ID Token row reuses the existing copy control and "Decode JWT"
  toggle rather than duplicating them. Access-token behavior is unchanged.
- `oauthDetailsFromConnectionState` now surfaces `tokens.id_token` as
  `idToken`, omitted entirely when absent so no empty row renders.
- Docs: update the two `specification/` references to the renamed field.

This is deliberately a viewer, not a flow: no OIDC login mode, no signature
verification, and the `id_token` is never treated as a credential. The EMA
path is untouched. `id_token` is already in `maskSecrets`'
`JSON_SENSITIVE_KEYS`, so it stays masked in the Network tab — no gap.

Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/components/groups/ConnectionInfoContent/oauthDetailsFromConnectionState.ts

@@ -22,6 +22,11 @@ export function oauthDetailsFromConnectionState(
     ...(state.tokens?.access_token && {
       accessToken: state.tokens.access_token,
     }),
+    // Surfaced for inspection when the AS returned one; omitted entirely
+    // otherwise so Connection Info renders no empty row (#2019).
+    ...(state.tokens?.id_token && {
+      idToken: state.tokens.id_token,
+    }),
     ...(state.protocol === "ema" &&
       state.ema?.idpSession && { idpSession: state.ema.idpSession }),
   };