fix(visualizer): make Deep Think a tri-state control so env reasoningEnabled is respected

[quanru]

Summary

• The Playground Deep Think checkbox previously defaulted to false, which always overrode MIDSCENE_MODEL_REASONING_ENABLED from env config — users who set it to true still saw thinking=false in logs.
• Changed Deep Think from a binary Checkbox to a tri-state Radio control (Auto / On / Off):
  • Auto (default): does not pass deepThink, so MIDSCENE_MODEL_REASONING_ENABLED env variable controls reasoning behavior. A tooltip on "Auto" explains this.
  • On: passes deepThink=true, force-enables reasoning.
  • Off: passes deepThink=false, force-disables reasoning.
• Updated store type from boolean to boolean | 'unset', with proper localStorage persistence and restoration.

Test plan

• Fresh Playground (no localStorage) + MIDSCENE_MODEL_REASONING_ENABLED=true → reasoning should be enabled (check ai-call.log)
• Fresh Playground + MIDSCENE_MODEL_REASONING_ENABLED=false → reasoning should be disabled
• Select "On" → reasoning force-enabled regardless of env
• Select "Off" → reasoning force-disabled regardless of env
• Select "Auto" → env variable controls reasoning
• Hover over "Auto" radio → tooltip shows env variable name
• Toggle flow: Auto → On → Off → Auto, refresh page, verify state persists correctly
• Non-aiAct actions should never forward deepThink

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[chatgpt-codex-connector]

Rebuild @midscene/visualizer dist for the new tri-state API

@midscene/visualizer is consumed through its published dist/* entrypoints (packages/visualizer/package.json points main/module/types there), but this commit only updates src/*. The checked-in build artifacts are still on the old boolean implementation (packages/visualizer/dist/lib/component/config-selector/index.js still renders a checkbox, and packages/visualizer/dist/types/store/store.d.ts still declares deepThink: boolean), so apps importing @midscene/visualizer such as packages/playground-app/src/PlaygroundApp.tsx and apps/report/src/components/playground/index.tsx will keep the pre-fix behavior until the package is rebuilt and the generated files are committed.

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