docs: ai 协作文档体系重构与多 ai 仲裁结果落地

1.AI 协作文档体系重构(objections/worklines/contracts+matrix.md)

2.coord 仲裁文档(final-decisions/cross-review/final-rulings/orchestration)

3.各服务 01/02 文档补全

4.共享包初始化(shared-ts/shared-go/hooks/ui-components/ui-tokens)

5.Proto 契约补全

6.004 架构影响地图更新

7.端口分配表

8.设计规格文档

packages/shared-go/env/env.go

@@ -0,0 +1,76 @@
+// Package env provides typed helpers for reading environment variables.
+//
+// All functions treat an unset variable and an empty string as distinct only
+// when explicitly documented: Must/Get distinguish "not set" from "set to empty"
+// via os.LookupEnv, while GetInt/GetBool/GetDuration fall back to the default
+// value when parsing fails.
+package env
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+)
+
+// Must returns the value of the environment variable named by key.
+// It panics if the variable is not set, which is intended for values that the
+// service cannot start without (DB URLs, JWT secrets, ...).
+func Must(key string) string {
+	v, ok := os.LookupEnv(key)
+	if !ok {
+		panic(fmt.Sprintf("env: required environment variable %q is not set", key))
+	}
+	return v
+}
+
+// Get returns the value of the environment variable named by key, or
+// defaultValue when the variable is not set.
+func Get(key, defaultValue string) string {
+	if v, ok := os.LookupEnv(key); ok {
+		return v
+	}
+	return defaultValue
+}
+
+// GetInt returns the integer value of the environment variable named by key,
+// or defaultValue when the variable is not set or cannot be parsed as an int.
+func GetInt(key string, defaultValue int) int {
+	if v, ok := os.LookupEnv(key); ok {
+		n, err := strconv.Atoi(v)
+		if err != nil {
+			return defaultValue
+		}
+		return n
+	}
+	return defaultValue
+}
+
+// GetBool returns the boolean value of the environment variable named by key,
+// or defaultValue when the variable is not set or cannot be parsed as a bool
+// (accepted values are those understood by strconv.ParseBool: 1, t, T, TRUE,
+// true, True, 0, f, F, FALSE, false, False).
+func GetBool(key string, defaultValue bool) bool {
+	if v, ok := os.LookupEnv(key); ok {
+		b, err := strconv.ParseBool(v)
+		if err != nil {
+			return defaultValue
+		}
+		return b
+	}
+	return defaultValue
+}
+
+// GetDuration returns the duration value of the environment variable named by
+// key, or defaultValue when the variable is not set or cannot be parsed by
+// time.ParseDuration (e.g. "30s", "5m", "2h").
+func GetDuration(key string, defaultValue time.Duration) time.Duration {
+	if v, ok := os.LookupEnv(key); ok {
+		d, err := time.ParseDuration(v)
+		if err != nil {
+			return defaultValue
+		}
+		return d
+	}
+	return defaultValue
+}