fix: address PR #757 review comments

- Extract getNvmWindowsCliPaths() helper to DRY up NVM_SYMLINK logic
- Update DEFAULT_MODELS.codex to gpt53Codex
- Simplify redundant ternary in thinking-level-selector
- Replace local supportsReasoningEffort with shared import from @automaker/types
- Use model.id fallback in phase-model-selector thinking level resolution

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/ui/src/components/views/settings-view/model-defaults/phase-model-selector.tsx

@@ -1297,7 +1297,7 @@ export function PhaseModelSelector({
                 Thinking Level
               </div>
               {getThinkingLevelsForModel(
-                model.mapsToClaudeModel === 'opus' ? 'claude-opus' : ''
+                model.mapsToClaudeModel === 'opus' ? 'claude-opus' : model.id || ''
               ).map((level) => (
                 <button
                   key={level}
@@ -1406,7 +1406,7 @@ export function PhaseModelSelector({
                 Thinking Level
               </div>
               {getThinkingLevelsForModel(
-                model.mapsToClaudeModel === 'opus' ? 'claude-opus' : ''
+                model.mapsToClaudeModel === 'opus' ? 'claude-opus' : model.id || ''
               ).map((level) => (
                 <button
                   key={level}