feat(compose): 正文内嵌隐藏块并升级 Markdown 编辑器

去掉整帖可见性表单，改为 :::hide 按块脱敏；工具栏补齐代码块、链接/图片对话框与粘贴拖拽上传。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/markdown/hide_test.go

@@ -0,0 +1,122 @@
+package markdown
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseIgnoreCodeFence(t *testing.T) {
+	src := "公开\n\n```\n:::hide login\n假的\n:::\n```\n\n结尾\n"
+	blocks, err := ParseHideBlocks(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(blocks) != 0 {
+		t.Fatalf("expected 0 blocks, got %d", len(blocks))
+	}
+}
+
+func TestParseMixedAndDerive(t *testing.T) {
+	src := "公开段\n\n:::hide login\n登录内容\n:::\n\n:::hide points 10\n积分A\n:::\n\n:::hide points 5\n积分B\n:::\n"
+	blocks, err := ParseHideBlocks(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(blocks) != 3 {
+		t.Fatalf("expected 3 blocks, got %d", len(blocks))
+	}
+	d := DeriveAccess(blocks)
+	if d.Access != "mixed" {
+		t.Fatalf("access=%s", d.Access)
+	}
+	if d.Points != 15 {
+		t.Fatalf("points=%d", d.Points)
+	}
+}
+
+func TestParseNestedRejected(t *testing.T) {
+	src := ":::hide login\n外\n:::hide reply\n内\n:::\n:::\n"
+	_, err := ParseHideBlocks(src)
+	if err != ErrHideNested {
+		t.Fatalf("want ErrHideNested, got %v", err)
+	}
+}
+
+func TestSanitizeLocksBody(t *testing.T) {
+	src := "公开\n\n:::hide login\n秘密内容\n:::\n\n尾\n"
+	out, fully := SanitizeForViewer(src, ViewerCaps{})
+	if fully {
+		t.Fatal("should not be fully locked")
+	}
+	if strings.Contains(out, "秘密内容") {
+		t.Fatalf("leaked: %q", out)
+	}
+	if !strings.Contains(out, ":::hide login locked") {
+		t.Fatalf("missing locked marker: %q", out)
+	}
+	if !strings.Contains(out, "公开") || !strings.Contains(out, "尾") {
+		t.Fatalf("public parts lost: %q", out)
+	}
+}
+
+func TestSanitizeUnlockLogin(t *testing.T) {
+	src := ":::hide login\n秘密\n:::\n"
+	out, fully := SanitizeForViewer(src, ViewerCaps{LoggedIn: true})
+	if fully {
+		t.Fatal("should see content")
+	}
+	if !strings.Contains(out, "秘密") {
+		t.Fatalf("missing body: %q", out)
+	}
+	if strings.Contains(out, "locked") {
+		t.Fatalf("should not lock: %q", out)
+	}
+}
+
+func TestSanitizeBypass(t *testing.T) {
+	src := ":::hide points 9\n付费\n:::\n"
+	out, _ := SanitizeForViewer(src, ViewerCaps{Bypass: true})
+	if !strings.Contains(out, "付费") {
+		t.Fatalf("bypass failed: %q", out)
+	}
+}
+
+func TestSanitizePointsPaid(t *testing.T) {
+	src := ":::hide points 3\n付费文\n:::\n"
+	out, _ := SanitizeForViewer(src, ViewerCaps{LoggedIn: true, PointsPaid: true})
+	if !strings.Contains(out, "付费文") {
+		t.Fatalf("paid unlock failed: %q", out)
+	}
+}
+
+func TestFullyLocked(t *testing.T) {
+	src := ":::hide reply\n仅回复\n:::\n"
+	_, fully := SanitizeForViewer(src, ViewerCaps{LoggedIn: true})
+	if !fully {
+		t.Fatal("expected fully locked")
+	}
+}
+
+func TestCodeInsideHide(t *testing.T) {
+	src := ":::hide login\n```\n:::hide reply\n伪\n:::\n```\n真\n:::\n"
+	blocks, err := ParseHideBlocks(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(blocks) != 1 {
+		t.Fatalf("got %d", len(blocks))
+	}
+	if !strings.Contains(blocks[0].Body, "真") {
+		t.Fatalf("body=%q", blocks[0].Body)
+	}
+}
+
+func TestWrapContentAsHide(t *testing.T) {
+	got := WrapContentAsHide("points", 20, "旧正文")
+	if !strings.HasPrefix(got, ":::hide points 20\n") {
+		t.Fatalf("%q", got)
+	}
+	if !strings.Contains(got, "旧正文") {
+		t.Fatal(got)
+	}
+}