test: _extract_content_units 仅统计功能章节表格行 - Closes #33

非功能章节（变更日志、术语解释等）的表格行不可能被
function_units 覆盖，计入分母会导致覆盖率虚低。

修复: table_rows 统计仅在 _is_functional_section
且 _has_section_content 的章节中进行。

Table 覆盖率: 54.2% → 72.2% (24行→18行分母)

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

tests/acceptance/test_main_health.py

@@ -137,16 +137,22 @@ def _extract_content_units(parsed_data: dict) -> dict:
 
     for sec in sections:
         name = sec.get("source", "")
-        if _is_functional_section(name) and _has_section_content(sec):
+        is_func = _is_functional_section(name) and _has_section_content(sec)
+        if is_func:
             functional_sections.append({
                 "name": name,
                 "number": _section_number(name),
             })
 
-        for block in sec.get("blocks", []):
-            if block.get("type") == "table":
-                rows = block.get("rows", [])
-                total_table_rows += len(rows)
+        # Only count table rows from functional sections
+        # (non-functional sections like changelog, glossary, references
+        #  cannot be covered by function_units — counting them inflates
+        #  the denominator and yields misleadingly low coverage.)
+        if is_func:
+            for block in sec.get("blocks", []):
+                if block.get("type") == "table":
+                    rows = block.get("rows", [])
+                    total_table_rows += len(rows)
 
     # Diagram-type images from image_analysis
     diagram_rids: list[str] = []