v2.4.4

PDF Craft v2.4.4

PDF Craft 2.4.4 fixes bilingual PDF-to-Markdown and PDF-to-EPUB conversion with
SubmitKind.APPEND_BLOCK. In 2.4.3, translation could finish successfully but
conversion would fail before rendering with contains duplicate fragment identity.

One-shot translation and bilingual output

• One-shot conversion now uses the same separate source and replacement-only
  translation layers as translate_extraction(). Bilingual content is combined
  only for rendering, preserving fragment identities and bounding boxes in each
  stored layer. Source-identity validation remains strict.
• All three submission modes retain distinct presentation: REPLACE displays
  the translation, APPEND_TEXT appends translated content within each matching
  source fragment, and APPEND_BLOCK displays each source body paragraph followed
  by its translated paragraph. One-shot conversion explicitly selects the new
  translation even when earlier translation layers exist.
• Added RenderMode.BILINGUAL_TEXT for the same-flow presentation when rendering
  stored translations. Existing RenderMode.BILINGUAL retains paragraph-based
  presentation. Headings and table-of-contents titles remain combined titles.
• Images and tables appear once in bilingual output. Translated asset fields are
  matched before bilingual paragraphs alter display positions, and table text is
  combined within cells. Repeated EPUB footnote references have unique link IDs
  while sharing one definition. Explicit preserved footnote coverage retains
  source text; older layers without footnote coverage keep their existing behavior.

The PCEX archive format, existing source identities, one-shot EPUB language
selection, and replacement-only PDF writeback remain unchanged. Submission modes
for translating an existing EPUB are unchanged.

Regression coverage

Tests reproduce the original failure before the fix and exercise the public
synchronous and asynchronous Markdown/EPUB conversion APIs in all three modes.
They run actual XML submission, workspace validation and rendering with
deterministic translation responses, covering multi-fragment paragraphs,
headings, footnotes, assets, preserved content and stored-layer round trips.

See #512.

Full Changelog: v2.4.3...v2.4.4