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phases/4-semantic-enrichment/step1.md

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+# Step 1: paragraph-stitching
+
+## Read First
+- /AGENTS.md
+- /PLAN.md
+- /PROGRESS.md
+- /docs/HARNESS.md
+- /docs/IMPLEMENTATION_PLAN.md
+- /docs/CONVERSION_POLICY.md
+- /phases/4-semantic-enrichment/step0.md
+
+## Task
+Implement paragraph stitching for line-fragmented PDF text blocks.
+
+Handle continuation lines and hyphenated line breaks while preserving likely compound words or identifiers when confidence is low.
+
+## Sprint Contract
+- Done means: paragraph stitching turns line fragments into coherent paragraph blocks with focused tests.
+- Hard thresholds: hyphen joins are tested; low-confidence hyphen cases are preserved; list items and headings are not merged into paragraphs.
+- Files owned: `src/pdftomd/enrichment.py`, tests, `PROGRESS.md`, phase index.
+- Dependencies: Step 0 checks and normalized block model.
+
+## Acceptance Criteria
+```powershell
+python scripts\validate_workspace.py
+.\venv\python.exe -m pytest tests
+```
+
+## Verification
+1. Run the acceptance commands.
+2. Confirm Korean and English text fixtures remain stable.
+3. Update `PROGRESS.md` and this phase index.
+
+## Do Not
+- Do not rely only on punctuation rules when bounding-box hints exist.
+- Do not merge across tables, figures, or formulas.
+- Do not modify source PDF files.