PDF Craft v2.6.6

PDF Craft 2.6.6 fixes concurrent PDF extraction, footnote OCR masks, XML fill
whitespace recovery, and chapter consistency after refinement. Downstream content
now comes from one finalized extraction result.

Migration from 2.6.5

• Extraction PAGE progress now uses stages 0–7 (max_stage=7). Update numeric
  labels: the previous OCR-persisted/JEV/LLM/final stages 2/3/4/5 become 4/5/6/7.
  First OCR, second-pass image preparation and second OCR have separate entry
  events. Async PDF pre-rendering remains in stage 0. See the
  stage table.
  #552,
  #553.
• Extraction on_body / on_footnote callbacks now deliver finalized, validated
  content once, after optional refinement and chapter assembly. The first content
  callback arrives later; use on_extraction_event for live progress. Callback
  delivery is not a task-success signal. Metadata may still arrive earlier.
• Derived TOC, chapter and furniture files are rebuilt from adopted content;
  existing toc.xml is no longer trusted as input. Valid raw OCR caches remain
  reusable. Re-extraction may assign different chapter IDs; existing PCEX files
  retain their format and identities. See streaming and cache migration.

Fixes

• Fix PCEX translation end-of-input races: title-dependent furniture waits for its
  producer, and body/footnote callbacks drain the final content exactly once in
  channel order. Failed or cancelled input scans are not successful EOF. Queue
  emptiness is checked after observing successful production completion.

• Serialize live page consumption across concurrent preparation/completion events,
  fixing duplicate pages and KeyError. Isolate blocking analysis and rendering
  workers from the short-IO pool, coordinate cancellation and callback draining,
  and settle concurrent work-unit completion only once.
  #560.

• Finalize traditional/refined content before deriving chapter IDs, TOC and
  furniture. Removing or merging a heading no longer leaves stale directory
  anchors; furniture uses final ownership. Formal content callbacks match adopted
  chapters. Private disk chunks bound intermediate aggregation without restoring
  pre-refinement directory constraints.
  #561.

• Preserve the complete union of first-pass OCR redaction masks. A lower, narrower
  text box no longer leaves the right side of a wider box exposed to the second
  footnote pass, preventing duplicate recognition from that leak.
  #554.

• Share document-whitespace semantics across friendly XML, segmentation and fill
  recovery. Preserve inline word boundaries and special spaces; reconstruct
  unambiguous canonical whitespace instead of spending another LLM request.
  Protected contexts retain their semantics; ambiguous allocation and changed
  words or punctuation still require correction. See LLM acceptance.
  #556,
  #558.

• Allocate merged canonical formulas through immutable math references, retain
  required empty source slots, and keep boundary spaces outside formula content
  that will be replaced. Accepted separators survive source-formula restoration.
  #557,
  #559.

• Preserve mixed-content text when serializing ordinary and streamed PCEX chapters;
  XML indentation no longer inserts separators between adjacent formulas.
  #555.

PCEX v4 and the progress event object structure are unchanged. The PAGE stage
numbers and extraction content-callback timing changes above require attention.

Full Changelog: v2.6.5...v2.6.6