Merge viewport creation fixes and current upstream into associations

tests/fixtures/embedded-image-print.md

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+Synthetic regression fixture for #1266. Generated with ezdxf/Pillow from basic
+geometry; it contains no external references or customer drawing content.
+
+Layout1 has an INSERT of SyntheticImage at (2, 4). That block contains one
+OLE2FRAME whose compound-file CONTENTS stream embeds a 64 x 32 BMP: red on
+the left, blue on the right, with a green diagonal from top-left to bottom-right.
+The frame occupies (0, 0) to (2, 1) in the block. Text and a triangle provide
+vector controls for manually opening the fixture and checking Plot Preview.