IB-WP-0016-T01: spine-aware EPUB3 intake

Parse META-INF/container.xml and the OPF package document, then iterate
documents in spine reading order instead of archive-name sort. Classify
each spine item (body, cover, nav, toc, header, footer, notes, license,
auxiliary) and exclude non-body sections by default; include_non_body=True
opts them back in for inspection. Capture OPF book metadata (title,
creator, language, subjects, rights, identifier, source_url, modified)
onto every chunk and propagate it through source artifact provenance.
Preserve the legacy zip-without-OPF fallback for malformed EPUBs.

Real Lefevre EPUB now yields 148 body chunks in spine order (was 155
mixed, archive-sorted) with cover=1, header=1, footer=4 detected and
dropped. 78 tests pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/lefevre-epub3-validation.md

@@ -68,3 +68,24 @@ able to show:
 - selected chapter or chunk filters for smoke runs
 - deterministic fixture acceptance on a small Lefevre-like subset
 - optional live one-chapter smoke run with explicit provider/model/cost caps
+
+## T01 Result (2026-05-17)
+
+Spine-aware EPUB3 intake landed. Re-running the local Lefevre EPUB through
+`normalize_source(...)` now yields:
+
+- 148 body chunks (default), down from the original 155 mixed chunks
+- Spine reading order: indices 0..27 in declared order, not archive-name sort
+- Full OPF metadata on every chunk's `book_metadata`:
+  title, creator, language, subjects, rights, identifier, source_url, modified
+- Section roles classified across the 154 spine items:
+  `body=148`, `footer=4`, `cover=1`, `header=1`
+- The four Gutenberg footer/license/notes sections and the `*** START OF…`
+  header section are now excluded from generation input by default and
+  available via `include_non_body=True` for inspection
+- The legacy zip-without-OPF fallback path is preserved for malformed EPUBs
+
+The remaining gap is title collapse: all body sections still share the
+Project Gutenberg page title because chapter headings are not yet read from
+in-document `<h1>` content. That collapse is T02's scope (chapter-aware
+chunking and stable IDs from in-document headings).