Add ISO A4 PDF print/book pipeline, page-frame prompts, and usage docs

Print and book PDF modes now letterbox each raster to A4 portrait at pdf.density;
print uses the matte color for pads. CLI forces 3:4 generation for print|book unless
--aspect-ratio is set. Cover, gallery, and back prompts gain DINA4PDF instructions when
those modes are active.

Introduce DescribePageFrame and PDF helpers with tests; add CLI tests for presentation
and aspect precedence. Expand README and config example with A4 examples, language
env vars, and page-format vs PDF behavior. Add sample Sumer vocabulary files.

Made-with: Cursor

1 files changed, 22 insertions, 0 deletions

diff --git a/internal/comic/pageframe_test.go b/internal/comic/pageframe_test.go
new file mode 100644
index 0000000..c9c7c26
--- /dev/null
+++ b/internal/comic/pageframe_test.go
@@ -0,0 +1,22 @@
+package comic
+
+import "testing"
+
+func TestDescribePageFrame(t *testing.T) {
+	tests := []struct {
+		ratio string
+		want  string
+	}{
+		{"16:9", "landscape 16:9 format (widescreen)"},
+		{"2:3", "portrait 2:3 format (tall comic book page proportions)"},
+		{"3:2", "landscape 3:2 format (widescreen)"},
+		{"1:1", "square 1:1 format"},
+		{"", "landscape 16:9 format (widescreen)"},
+		{"bogus", "bogus format"},
+	}
+	for _, tt := range tests {
+		if got := DescribePageFrame(tt.ratio); got != tt.want {
+			t.Fatalf("DescribePageFrame(%q) = %q, want %q", tt.ratio, got, tt.want)
+		}
+	}
+}