refactor(tui): migrate dialog views to V2 themes

[jlongster]

Summary

• migrate ten dialog and lifecycle views from flat V1 colors to semantic V2 tokens
• use elevated contextual tokens for dialog surfaces
• preserve selected button contrast with paired focused action tokens

Verification

• bun typecheck
• bun test test/cli/tui/dialog-prompt.test.tsx test/cli/tui/dialog-select.test.tsx --timeout 30000 (8 passed)
• git diff --check

OpenCode Drive screenshots will be attached in a follow-up comment.

[jlongster]

OpenCode Drive visual verification

Captured from this branch with isolated simulated projects. Each migrated file is represented below.

Pair dialog

packages/tui/src/component/dialog-pair.tsx

Status dialog

packages/tui/src/component/dialog-status.tsx

Project copy name

packages/tui/src/component/dialog-project-copy-name.tsx

Missing plugin route

packages/tui/src/component/plugin-route-missing.tsx

Reconnecting overlay

packages/tui/src/component/reconnecting.tsx

Startup loading

packages/tui/src/component/startup-loading.tsx

Help dialog

packages/tui/src/ui/dialog-help.tsx

Alert dialog

packages/tui/src/ui/dialog-alert.tsx

Export result

packages/tui/src/ui/dialog-export-result.tsx

Confirm dialog

packages/tui/src/ui/dialog-confirm.tsx