New profiles now store renderer `wasm` in their props at creation, so
every signup path (email, OIDC, LDAP, Nitrate, demo, CLI) starts on
WebGL. A renderer passed by the caller still wins.
Existing profiles without a stored renderer keep the frontend fallback
to SVG, so no backfill or version check is needed to leave them as they
are.
The `register-profile` audit event gains `renderer-default` when the
profile is created in that call, so signups before and after this
change can be told apart.
Closes#11855
AI-assisted-by: claude-opus-5-5
988cde3c9d