Simplify approval cards for one-handed approve, deny, edit, and escalation #234

Goal

Reduce approval cards to risk, affected target, compact diff/input summary, and deliberate actions suited to a phone.

Scope

• Optimize for one-handed review, approval, and short intervention before full terminal use.
• Keep the default view comprehensible under slow, disconnected, or partially recovered fleet state.

Acceptance

• Reduce approval cards to risk, affected target, compact diff/input summary, and deliberate actions suited to a phone.
• Use semantic controls with touch targets and keyboard-accessible equivalents.
• Add DOM-level tests for loading, failure, and success states.

Verification

• npm --prefix frontend test

Dependencies

#233