fix(core): return 'opus' directly instead of mapping to 'inherit' (#1079)

resolveModelInternal() was converting 'opus' to 'inherit', assuming
the parent process runs on Opus. When the orchestrator runs on Sonnet
(the default), 'inherit' resolves to Sonnet — silently downgrading
quality profile subagents.

Remove the opus→inherit conversion so the resolved model name is
passed through directly. Claude Code's Task tool now supports model
aliases like 'opus', 'sonnet', 'haiku'.

Fixes #695

get-shit-done/bin/lib/core.cjs

@@ -374,7 +374,7 @@ function resolveModelInternal(cwd, agentType) {
   // Check per-agent override first
   const override = config.model_overrides?.[agentType];
   if (override) {
-    return override === 'opus' ? 'inherit' : override;
+    return override;
   }
 
   // Fall back to profile lookup
@@ -382,8 +382,7 @@ function resolveModelInternal(cwd, agentType) {
   const agentModels = MODEL_PROFILES[agentType];
   if (!agentModels) return 'sonnet';
   if (profile === 'inherit') return 'inherit';
-  const resolved = agentModels[profile] || agentModels['balanced'] || 'sonnet';
-  return resolved === 'opus' ? 'inherit' : resolved;
+  return agentModels[profile] || agentModels['balanced'] || 'sonnet';
 }
 
 // ─── Misc utilities ───────────────────────────────────────────────────────────