Align Go parser backends and PDF pipeline with Python (#16676)

Ports remaining Go parser wiring and PDF backends, adds tenant-aware VLM
dispatch, aligns post-processing with Python, and adds end-to-end
pipeline coverage with a generated six-page PDF.

internal/parser/parser/pdf_postprocess_test.go

@@ -0,0 +1,140 @@
+package parser
+
+import (
+	"testing"
+
+	deepdoctype "ragflow/internal/deepdoc/parser/type"
+)
+
+func makePDFSection(text, layout string, page int, left, right, top, bottom float64) deepdoctype.Section {
+	return deepdoctype.Section{
+		Text:       text,
+		LayoutType: layout,
+		Positions: []deepdoctype.Position{{
+			PageNumbers: []int{page},
+			Left:        left,
+			Right:       right,
+			Top:         top,
+			Bottom:      bottom,
+		}},
+	}
+}
+
+func TestApplyPDFPostProcess_NormalizesLayoutTypes(t *testing.T) {
+	result := &deepdoctype.ParseResult{
+		Sections: []deepdoctype.Section{
+			{Text: "a", LayoutType: ""},
+			{Text: "b", LayoutType: "  "},
+			{Text: "c", LayoutType: "table"},
+			{Text: "d", LayoutType: "  figure  "},
+		},
+	}
+	applyPDFPostProcess(result, pdfPostProcessOptions{})
+	want := []string{"text", "text", "table", "figure"}
+	for i, s := range result.Sections {
+		if s.LayoutType != want[i] {
+			t.Fatalf("Sections[%d].LayoutType = %q, want %q", i, s.LayoutType, want[i])
+		}
+	}
+}
+
+func TestApplyPDFPostProcess_AssignsDocTypeKeywords(t *testing.T) {
+	result := &deepdoctype.ParseResult{
+		Sections: []deepdoctype.Section{
+			{Text: "a", LayoutType: "table"},
+			{Text: "b", LayoutType: "figure"},
+			{Text: "c", LayoutType: "text"},
+			{Text: "d", LayoutType: "", Image: "abc"},
+		},
+	}
+	applyPDFPostProcess(result, pdfPostProcessOptions{})
+	want := []string{"table", "image", "text", "image"}
+	for i, s := range result.Sections {
+		if s.DocTypeKwd != want[i] {
+			t.Fatalf("Sections[%d].DocTypeKwd = %q, want %q", i, s.DocTypeKwd, want[i])
+		}
+	}
+}
+
+func TestApplyPDFPostProcess_FlattenMediaKeepsImagesButMarksText(t *testing.T) {
+	result := &deepdoctype.ParseResult{
+		Sections: []deepdoctype.Section{
+			{Text: "a", LayoutType: "figure", Image: "abc"},
+			{Text: "b", LayoutType: "table"},
+		},
+	}
+	applyPDFPostProcess(result, pdfPostProcessOptions{flattenMediaToText: true})
+	for i, s := range result.Sections {
+		if s.DocTypeKwd != "text" {
+			t.Fatalf("Sections[%d].DocTypeKwd = %q, want text", i, s.DocTypeKwd)
+		}
+	}
+	if got, want := result.Sections[0].Image, "abc"; got != want {
+		t.Fatalf("Sections[0].Image = %q, want %q", got, want)
+	}
+}
+
+func TestApplyPDFPostProcess_HeaderFooterFilteringIsOptional(t *testing.T) {
+	result := &deepdoctype.ParseResult{
+		Sections: []deepdoctype.Section{
+			{Text: "header", LayoutType: "header"},
+			{Text: "body", LayoutType: "text"},
+		},
+	}
+	applyPDFPostProcess(result, pdfPostProcessOptions{})
+	if len(result.Sections) != 2 {
+		t.Fatalf("len(Sections) = %d, want 2 when removeHeaderFooter is false", len(result.Sections))
+	}
+
+	applyPDFPostProcess(result, pdfPostProcessOptions{removeHeaderFooter: true})
+	if len(result.Sections) != 1 {
+		t.Fatalf("len(Sections) = %d, want 1 when removeHeaderFooter is true", len(result.Sections))
+	}
+	if got, want := result.Sections[0].Text, "body"; got != want {
+		t.Fatalf("remaining section = %q, want %q", got, want)
+	}
+}
+
+func TestApplyPDFPostProcess_RemoveTOCByOutlines(t *testing.T) {
+	result := &deepdoctype.ParseResult{
+		Sections: []deepdoctype.Section{
+			makePDFSection("目录", "text", 1, 50, 550, 100, 120),
+			makePDFSection("章节列表", "text", 2, 50, 550, 120, 140),
+			makePDFSection("正文", "text", 3, 50, 550, 100, 120),
+		},
+		Outlines: []deepdoctype.Outline{
+			{Title: "目录", Level: 0, PageNumber: 1},
+			{Title: "第一章", Level: 0, PageNumber: 3},
+		},
+	}
+	applyPDFPostProcess(result, pdfPostProcessOptions{removeTOC: true})
+	if len(result.Sections) != 1 {
+		t.Fatalf("len(Sections) = %d, want 1", len(result.Sections))
+	}
+	if got, want := result.Sections[0].Text, "正文"; got != want {
+		t.Fatalf("remaining section = %q, want %q", got, want)
+	}
+}
+
+func TestApplyPDFPostProcess_ReordersMultiColumnText(t *testing.T) {
+	cases := []struct {
+		name      string
+		pageWidth float64
+		zoom      float64
+	}{
+		{name: "unit zoom", pageWidth: 600, zoom: 1},
+		{name: "pre-normalized width", pageWidth: 200, zoom: 3},
+	}
+	for _, tc := range cases {
+		result := &deepdoctype.ParseResult{
+			Sections: []deepdoctype.Section{
+				makePDFSection("right", "text", 0, 100, 166, 100, 120),
+				makePDFSection("left", "text", 0, 10, 76, 100, 120),
+			},
+		}
+		applyPDFPostProcess(result, pdfPostProcessOptions{pageWidth: tc.pageWidth, zoom: tc.zoom, enableMultiColumn: true})
+		if got, want := result.Sections[0].Text, "left"; got != want {
+			t.Fatalf("%s: Sections[0].Text = %q, want %q", tc.name, got, want)
+		}
+	}
+}