feat(t52): per-folder 庫章——DirectConfig.libraries 對映＋libraryFor()（資料夾名 slug／中文退後備／明列優先，go test 綠）；兩支 ingest workflow 的 post_block metadata 補 library（真兇：blocks 沒蓋章＝兩資料夾全歸 general）；托盤連線時回報庫自動登記

t52_library_test.go

@@ -0,0 +1,22 @@
+package main
+
+import "testing"
+
+func TestLibraryPerFolder(t *testing.T) {
+	cfg := &DirectConfig{Library: "kb"}
+	cases := map[string]string{
+		"/Users/x/Desktop/finance":     "finance",
+		"/Users/x/Desktop/HR Docs":     "hr_docs",
+		"/Users/x/Desktop/官方總圖":       "kb",
+		"/Users/x/Desktop/test 01":     "test_01",
+	}
+	for in, want := range cases {
+		if got := cfg.libraryFor(in); got != want {
+			t.Errorf("libraryFor(%q) = %q, want %q", in, got, want)
+		}
+	}
+	cfg.Libraries = map[string]string{"/Users/x/Desktop/官方總圖": "official"}
+	if got := cfg.libraryFor("/Users/x/Desktop/官方總圖"); got != "official" {
+		t.Errorf("明列對映應優先，got %q", got)
+	}
+}