feat: 新增账户资料页与头像上传

将工作人员和用户的详情、编辑改为独立账户资料页。

增加受控头像上传与读取、图片安全校验、接口测试，并优化只读及编辑布局。

同步更新平台需求、接口安全说明、项目文档和操作日志。

backend/api/internal/logic/upload/avatar_test.go

@@ -0,0 +1,70 @@
+// Package upload 测试头像上传的格式、尺寸与路径安全边界。
+// 版本：v1.0.0
+package upload
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/png"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// pngBytes 生成指定尺寸的有效 PNG 测试图片。
+func pngBytes(t *testing.T, width, height int) []byte {
+	t.Helper()
+	picture := image.NewRGBA(image.Rect(0, 0, width, height))
+	picture.Set(0, 0, color.RGBA{R: 32, G: 96, B: 192, A: 255})
+	var buffer bytes.Buffer
+	if err := png.Encode(&buffer, picture); err != nil {
+		t.Fatalf("encode PNG: %v", err)
+	}
+	return buffer.Bytes()
+}
+
+// TestValidateAvatarAcceptsRealPNG 验证真实 PNG 可通过并规范化类型。
+func TestValidateAvatarAcceptsRealPNG(t *testing.T) {
+	extension, contentType, err := validateAvatar("头像.PNG", pngBytes(t, 2, 2))
+	if err != nil {
+		t.Fatalf("valid PNG was rejected: %v", err)
+	}
+	if extension != ".png" || contentType != "image/png" {
+		t.Fatalf("avatar metadata = (%q, %q)", extension, contentType)
+	}
+}
+
+// TestValidateAvatarRejectsSpoofedAndOversizedImage 验证伪造扩展名与超大像素尺寸会被拒绝。
+func TestValidateAvatarRejectsSpoofedAndOversizedImage(t *testing.T) {
+	if _, _, err := validateAvatar("fake.png", []byte("not an image")); err == nil {
+		t.Fatal("spoofed PNG was accepted")
+	}
+	if _, _, err := validateAvatar("wide.png", pngBytes(t, maxAvatarDimension+1, 1)); err == nil {
+		t.Fatal("oversized image dimensions were accepted")
+	}
+}
+
+// TestAvatarPathFromURIStaysInsideControlledRoot 验证头像 URI 不能逃逸受控目录。
+func TestAvatarPathFromURIStaysInsideControlledRoot(t *testing.T) {
+	root := t.TempDir()
+	t.Setenv("HEQI_UPLOAD_DIR", root)
+	path, err := avatarPathFromURI("/uploads/avatars/2026/08/10/example.png")
+	if err != nil {
+		t.Fatalf("controlled URI was rejected: %v", err)
+	}
+	expectedRoot := filepath.Join(root, "avatars")
+	relative, err := filepath.Rel(expectedRoot, path)
+	if err != nil || relative == ".." || strings.HasPrefix(relative, ".."+string(filepath.Separator)) {
+		t.Fatalf("avatar path escaped root: %q", path)
+	}
+	for _, uri := range []string{
+		"https://example.com/avatar.png",
+		"/uploads/example.png",
+		"/uploads/avatars/../../secret.png",
+	} {
+		if _, err := avatarPathFromURI(uri); err == nil {
+			t.Fatalf("unsafe avatar URI was accepted: %q", uri)
+		}
+	}
+}