Harden reconnect, offline, loading, and failure states for fleet navigation #237

Goal

Present actionable reconnect and stale-data states without hiding pending approvals or accidentally duplicating commands.

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

• Present actionable reconnect and stale-data states without hiding pending approvals or accidentally duplicating commands.
• 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

#212, #213, #216