Blank-line paragraph segmentation (whitespace-only lines as boundaries,
blank lines themselves never in any chunk's range). Paragraphs > 80 lines
split into 80-line windows with 20-line overlap (stride 60), sharing the
input lang and symbol=None per spec §9.3. tier2_shared exposes a new
build_chunk_no_symbol helper so Chunk id/hash/token semantics stay
identical with Tier 1/2. Extracts build_chunk_from_span as private core
so build_chunk and build_chunk_no_symbol share mechanics without drift.
4 unit tests cover multi-paragraph shell (4 paragraphs, blank-line
boundaries verified), 200-line oversize line-window split (chunks
1-80 / 61-140 / 121-200), empty file, and lang preservation when
input is yaml.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
altair823
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