feat(desktop): plumb ProviderEntry.reasoningLevel into generate calls

Closes the backend half of the per-provider reasoning-depth control.
The Settings UI dropdown ships as a follow-up.

- ActiveModelResolution gains reasoningLevel (undefined | 1 of 5 levels)
- resolveActiveModel() reads it from the ProviderEntry on disk
- All four generate call sites in main/index.ts forward active.reasoningLevel
  into core's GenerateInput / ApplyCommentInput
- Claude Code import seeds 'medium' on the imported ProviderEntry so
  consumer-tier proxies stop 400ing on higher levels

Author: hqhq1025

apps/desktop/src/main/imports/claude-code-config.ts

@@ -56,6 +56,11 @@ export function parseClaudeCodeSettings(json: string): ClaudeCodeImport {
     wire: 'anthropic',
     baseUrl,
     defaultModel: model,
+    // Claude Code proxies commonly gate reasoning effort by plan — the
+    // consumer-tier endpoint accepts only 'medium'. Seed this default so
+    // imports just work; higher-tier users can raise it in Settings →
+    // Providers → Reasoning depth.
+    reasoningLevel: 'medium',
   };
 
   if (apiKey === null) {

apps/desktop/src/main/provider-settings.ts

@@ -5,6 +5,7 @@ import {
   type ModelRef,
   PROVIDER_SHORTLIST,
   type ProviderEntry,
+  type ReasoningLevel,
   type WireApi,
   isSupportedOnboardingProvider,
 } from '@open-codesign/shared';
@@ -182,6 +183,7 @@ export interface ActiveModelResolution {
   wire: WireApi;
   httpHeaders: Record<string, string> | undefined;
   queryParams: Record<string, string> | undefined;
+  reasoningLevel: ReasoningLevel | undefined;
   /** True when the renderer-supplied hint provider didn't match the canonical active. */
   overridden: boolean;
 }
@@ -212,6 +214,7 @@ export function resolveActiveModel(
     wire: entry.wire,
     httpHeaders: entry.httpHeaders,
     queryParams: entry.queryParams,
+    reasoningLevel: entry.reasoningLevel,
     overridden,
   };
 }