feat(routing): RoutingConfig + LoadRouting

Typed config struct and env parser for the routing pod. Kept separate
from the supervisor Config to avoid forcing routing fields onto the
supervisor and vice versa. Uses the existing envOr helper from config.go.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/config/routing.go

@@ -0,0 +1,78 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+)
+
+// RoutingConfig holds the runtime configuration for the routing pod.
+// Separate from Config because the routing pod's surface differs from the supervisor's.
+type RoutingConfig struct {
+	Port               string  // ROUTING_PORT, default 3210
+	MCPAuthToken       string  // ROUTING_MCP_TOKEN, optional bearer token
+	LiteLLMBaseURL     string  // LITELLM_BASE_URL, default http://piguard:4000
+	LiteLLMAPIKey      string  // LITELLM_API_KEY
+	BrainURL           string  // BRAIN_URL, default http://ingestion.supervisor:3300
+	LocalModel         string  // HYPERGUILD_LOCAL_MODEL, default qwen35
+	ClaudeModel        string  // HYPERGUILD_CLAUDE_MODEL, default claude-sonnet-4-6
+	RouteLocalFloor    float64 // HYPERGUILD_ROUTE_LOCAL_FLOOR, default 0.90
+	RouteLocalCeil     float64 // HYPERGUILD_ROUTE_LOCAL_CEIL, default 0.70
+	PassRateTTLSeconds int     // HYPERGUILD_PASS_RATE_TTL_SECONDS, default 60
+}
+
+func LoadRouting() (RoutingConfig, error) {
+	cfg := RoutingConfig{
+		Port:           envOr("ROUTING_PORT", "3210"),
+		MCPAuthToken:   os.Getenv("ROUTING_MCP_TOKEN"),
+		LiteLLMBaseURL: envOr("LITELLM_BASE_URL", "http://piguard:4000"),
+		LiteLLMAPIKey:  os.Getenv("LITELLM_API_KEY"),
+		BrainURL:       envOr("BRAIN_URL", "http://ingestion.supervisor:3300"),
+		LocalModel:     envOr("HYPERGUILD_LOCAL_MODEL", "qwen35"),
+		ClaudeModel:    envOr("HYPERGUILD_CLAUDE_MODEL", "claude-sonnet-4-6"),
+	}
+
+	floor, err := parseFloatEnv("HYPERGUILD_ROUTE_LOCAL_FLOOR", 0.90)
+	if err != nil {
+		return RoutingConfig{}, err
+	}
+	cfg.RouteLocalFloor = floor
+
+	ceil, err := parseFloatEnv("HYPERGUILD_ROUTE_LOCAL_CEIL", 0.70)
+	if err != nil {
+		return RoutingConfig{}, err
+	}
+	cfg.RouteLocalCeil = ceil
+
+	ttl, err := parseIntEnv("HYPERGUILD_PASS_RATE_TTL_SECONDS", 60)
+	if err != nil {
+		return RoutingConfig{}, err
+	}
+	cfg.PassRateTTLSeconds = ttl
+
+	return cfg, nil
+}
+
+func parseFloatEnv(key string, def float64) (float64, error) {
+	v := os.Getenv(key)
+	if v == "" {
+		return def, nil
+	}
+	f, err := strconv.ParseFloat(v, 64)
+	if err != nil {
+		return 0, fmt.Errorf("config: %s: %w", key, err)
+	}
+	return f, nil
+}
+
+func parseIntEnv(key string, def int) (int, error) {
+	v := os.Getenv(key)
+	if v == "" {
+		return def, nil
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, fmt.Errorf("config: %s: %w", key, err)
+	}
+	return n, nil
+}