feat: enhance SDK options with thinking level support

- Introduced a new function, buildThinkingOptions, to handle the conversion of ThinkingLevel to maxThinkingTokens for the Claude SDK.
- Updated existing SDK option creation functions to incorporate thinking options, ensuring that maxThinkingTokens are included based on the specified thinking level.
- Enhanced the settings service to support migration of phase models to include thinking levels, improving compatibility with new configurations.
- Added comprehensive tests for thinking level integration and migration logic, ensuring robust functionality across the application.

This update significantly improves the SDK's configurability and performance by allowing for more nuanced control over reasoning capabilities.

apps/server/src/routes/backlog-plan/generate-plan.ts

@@ -7,7 +7,8 @@
 
 import type { EventEmitter } from '../../lib/events.js';
 import type { Feature, BacklogPlanResult, BacklogChange, DependencyUpdate } from '@automaker/types';
-import { DEFAULT_PHASE_MODELS, isCursorModel } from '@automaker/types';
+import { DEFAULT_PHASE_MODELS, isCursorModel, type ThinkingLevel } from '@automaker/types';
+import { resolvePhaseModel } from '@automaker/model-resolver';
 import { FeatureLoader } from '../../services/feature-loader.js';
 import { ProviderFactory } from '../../providers/provider-factory.js';
 import { extractJsonWithArray } from '../../lib/json-extractor.js';
@@ -107,10 +108,14 @@ export async function generateBacklogPlan(
 
     // Get the model to use from settings or provided override
     let effectiveModel = model;
+    let thinkingLevel: ThinkingLevel | undefined;
     if (!effectiveModel) {
       const settings = await settingsService?.getGlobalSettings();
-      effectiveModel =
+      const phaseModelEntry =
         settings?.phaseModels?.backlogPlanningModel || DEFAULT_PHASE_MODELS.backlogPlanningModel;
+      const resolved = resolvePhaseModel(phaseModelEntry);
+      effectiveModel = resolved.model;
+      thinkingLevel = resolved.thinkingLevel;
     }
     logger.info('[BacklogPlan] Using model:', effectiveModel);
 
@@ -154,6 +159,7 @@ ${userPrompt}`;
       abortController,
       settingSources: autoLoadClaudeMd ? ['user', 'project'] : undefined,
       readOnly: true, // Plan generation only generates text, doesn't write files
+      thinkingLevel, // Pass thinking level for extended thinking
     });
 
     let responseText = '';