feat(codeagent-wrapper): add reasoning effort config for codex backend

- Add --reasoning-effort CLI flag for codex model thinking intensity
- Support reasoning config in ~/.codeagent/models.json per agent
- CLI flag takes precedence over config file
- Only effective for codex backend

Closes #117

Generated with SWE-Agent.ai

Co-Authored-By: SWE-Agent.ai <noreply@swe-agent.ai>

codeagent-wrapper/executor.go

@@ -764,6 +764,10 @@ func buildCodexArgs(cfg *Config, targetArg string) []string {
 		args = append(args, "--model", model)
 	}
 
+	if reasoningEffort := strings.TrimSpace(cfg.ReasoningEffort); reasoningEffort != "" {
+		args = append(args, "--reasoning-effort", reasoningEffort)
+	}
+
 	args = append(args, "--skip-git-repo-check")
 
 	if isResume {
@@ -804,12 +808,13 @@ func runCodexTaskWithContext(parentCtx context.Context, taskSpec TaskSpec, backe
 	logger := injectedLogger
 
 	cfg := &Config{
-		Mode:      taskSpec.Mode,
-		Task:      taskSpec.Task,
-		SessionID: taskSpec.SessionID,
-		WorkDir:   taskSpec.WorkDir,
-		Model:     taskSpec.Model,
-		Backend:   defaultBackendName,
+		Mode:            taskSpec.Mode,
+		Task:            taskSpec.Task,
+		SessionID:       taskSpec.SessionID,
+		WorkDir:         taskSpec.WorkDir,
+		Model:           taskSpec.Model,
+		ReasoningEffort: taskSpec.ReasoningEffort,
+		Backend:         defaultBackendName,
 	}
 
 	commandName := codexCommand
@@ -846,6 +851,12 @@ func runCodexTaskWithContext(parentCtx context.Context, taskSpec TaskSpec, backe
 		}
 	}
 
+	// Load gemini env from ~/.gemini/.env if exists
+	var geminiEnv map[string]string
+	if cfg.Backend == "gemini" {
+		geminiEnv = loadGeminiEnv()
+	}
+
 	useStdin := taskSpec.UseStdin
 	targetArg := taskSpec.Task
 	if useStdin {
@@ -948,6 +959,9 @@ func runCodexTaskWithContext(parentCtx context.Context, taskSpec TaskSpec, backe
 	if cfg.Backend == "claude" && len(claudeEnv) > 0 {
 		cmd.SetEnv(claudeEnv)
 	}
+	if cfg.Backend == "gemini" && len(geminiEnv) > 0 {
+		cmd.SetEnv(geminiEnv)
+	}
 
 	// For backends that don't support -C flag (claude, gemini), set working directory via cmd.Dir
 	// Codex passes workdir via -C flag, so we skip setting Dir for it to avoid conflicts