Add thesis-like SEQ roundtrip fixture

[kiki830621]

Summary

• Add a shareable thesis-like roundtrip fixture for the #94/verify-with-user-fixture: real thesis docx roundtrip for #94 / che-word-mcp#94 #27 workflow.
• Cover 12 figure captions and 7 table captions inside table cells.
• Verify Writer -> Reader -> updateAllFields returns Figure: 12 and Table: 7.

Notes

• The real user thesis docx is not present in this repository, so this synthetic fixture does not replace Adam retesting the original document.
• It pins the closest repo-safe regression surface for the reported table-cell caption layout.

Tests

• swift test --filter Issue94UpdateAllFieldsContainerCoverageTests
• swift test

Refs #27