fix(tui): style destructive dialog actions - #40950

What

Give destructive DialogSelect footer actions a distinct keyboard-focus state while preserving the ordinary idle presentation.

Before / After

Before: Focused Delete and Disconnect actions used the same primary styling as benign actions such as Rename, New, and Refresh.

After: All actions look neutral at rest. Focused session Delete, stash Delete, project-copy Delete, and connected MCP Disconnect use destructive action colors; benign actions keep primary focus colors.

How

• Add a primary | destructive variant to shared DialogSelect actions.
• Resolve focused and disabled colors from the selected variant.
• Keep the existing neutral foreground when no footer action is focused.
• Mark the four existing destructive consumers without changing their behavior.

Scope

This PR changes focused action styling only. It does not change confirmation, default selection, deletion, or disconnect behavior. Safe-default confirmation remains tracked in #36302.

Testing

• bun typecheck from packages/tui
• bun run test test/cli/tui/dialog-select.test.tsx test/cli/cmd/tui/integration-options.test.ts
• Repository pre-push typecheck
• Inspected deterministic idle, Delete-focused, and Rename-focused PNG frames at 80x20
• git diff --check

Demo

The comparison moves from neutral idle state to destructive Delete focus, then ordinary Rename focus.