feat(admin): add routed task evidence details

admin/internal/config/config.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -21,6 +22,7 @@ const (
 	authorizationTTLEnv    = "CMBUYER_AUTHORIZATION_TTL"
 	maxTaskQuantityEnv     = "CMBUYER_MAX_TASK_QUANTITY"
 	maxTotalPriceEnv       = "CMBUYER_MAX_TOTAL_PRICE"
+	evidenceDirectoryEnv   = "CMBUYER_EVIDENCE_DIR"
 	minimumSecretLength    = 32
 )
 
@@ -34,6 +36,7 @@ type Config struct {
 	AuthorizationTTL    time.Duration
 	MaxTaskQuantity     int
 	MaxTotalPrice       string
+	EvidenceDirectory   string
 }
 
 // LoadFromEnv 从进程环境读取配置。错误只指出缺失或非法的变量名，绝不回显秘密。
@@ -102,6 +105,13 @@ func Load(lookup func(string) (string, bool)) (Config, error) {
 	if !canonicalMoney(maxPrice) {
 		return Config{}, fmt.Errorf("%s must be a canonical positive decimal", maxTotalPriceEnv)
 	}
+	evidenceDirectory, err := required(lookup, evidenceDirectoryEnv)
+	if err != nil {
+		return Config{}, err
+	}
+	if strings.TrimSpace(evidenceDirectory) != evidenceDirectory || !filepath.IsAbs(evidenceDirectory) {
+		return Config{}, fmt.Errorf("%s must be an absolute path without surrounding whitespace", evidenceDirectoryEnv)
+	}
 
 	return Config{
 		AdminUsername:       username,
@@ -110,6 +120,7 @@ func Load(lookup func(string) (string, bool)) (Config, error) {
 		CookieSecure:        cookieSecure,
 		DatabaseSource:      databaseSource,
 		AuthorizationTTL:    ttl, MaxTaskQuantity: maxQuantity, MaxTotalPrice: maxPrice,
+		EvidenceDirectory: evidenceDirectory,
 	}, nil
 }