Add explicit LLM concurrency controls

internal/core/config/env.go

@@ -68,12 +68,37 @@ func loadFromLookup(lookup func(string) (string, bool)) (Config, error) {
 		}
 		cfg.PrimaryLLM.MaxRetries = value
 	}
+	totalConcurrencySet := false
+	if raw, ok := lookup("AUDITA_TOTAL_LLM_CONCURRENCY"); ok {
+		value, err := parseInt(raw)
+		if err != nil {
+			return Config{}, fmt.Errorf("AUDITA_TOTAL_LLM_CONCURRENCY: %w", err)
+		}
+		cfg.TotalLLMConcurrency = value
+		totalConcurrencySet = true
+	}
 	if raw, ok := lookup("AUDITA_LLM_CONCURRENCY"); ok {
 		value, err := parseInt(raw)
 		if err != nil {
 			return Config{}, fmt.Errorf("AUDITA_LLM_CONCURRENCY: %w", err)
 		}
-		cfg.PrimaryLLM.Concurrency = value
+		if !totalConcurrencySet {
+			cfg.TotalLLMConcurrency = value
+			totalConcurrencySet = true
+		}
+	}
+
+	proposalConcurrencySet := false
+	if raw, ok := lookup("AUDITA_PROPOSAL_LLM_CONCURRENCY"); ok {
+		value, err := parseInt(raw)
+		if err != nil {
+			return Config{}, fmt.Errorf("AUDITA_PROPOSAL_LLM_CONCURRENCY: %w", err)
+		}
+		cfg.ProposalLLMConcurrency = value
+		proposalConcurrencySet = true
+	}
+	if totalConcurrencySet && !proposalConcurrencySet {
+		cfg.ProposalLLMConcurrency = cfg.TotalLLMConcurrency
 	}
 
 	if raw, ok := lookup("AUDITA_VALIDATION_MAX_RETRIES"); ok {
@@ -88,7 +113,7 @@ func loadFromLookup(lookup func(string) (string, bool)) (Config, error) {
 		if err != nil {
 			return Config{}, fmt.Errorf("AUDITA_VALIDATION_LLM_CONCURRENCY: %w", err)
 		}
-		cfg.ValidationLLM.Concurrency = &value
+		cfg.ValidationLLMConcurrency = &value
 	}
 
 	if raw, ok := lookup("AUDITA_VALIDATION_MAX_PROMPT_TOKENS"); ok {
@@ -188,6 +213,8 @@ func loadFromLookup(lookup func(string) (string, bool)) (Config, error) {
 		cfg.WorkDirRetention = WorkDirRetention(raw)
 	}
 
+	cfg.syncLegacyConcurrencyAliases()
+
 	if err := cfg.Validate(); err != nil {
 		return Config{}, err
 	}