Update question wording and improve consistency across all six slices

[ksale001]

Summary

• Wording pass over the six assessment questions on top of First pass at validator beat #1. Builds on the new copy rather than rewriting it.
• Tightened the questions and removed the em dashes. Option labels now state the actual criteria, e.g. "combined share under ⅔ of the network" instead of "includes a minority client".
• Client diversity helper restructured into plain prose around its two safeguards. The Charon/Vero/Vouch config flags are out, tools still get a mention.
• Fraction labels (⅓/⅔) on provider and geo to match key custody.
• One meaning change to flag: the geo red sub now describes going offline rather than "could risk your validator's security". Regional concentration is a liveness risk, not a safety one.

How to test it

• yarn test and yarn lint pass (ran locally)
• Click through all six questions on the dev server