content: document normalization (normalize.sx) + 11 tests (605/605)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/content/scoreboard.md

@@ -20,6 +20,7 @@ _Generated by `lib/content/conformance.sh`_
 | query | 13 | 0 | 13 |
 | toc | 8 | 0 | 8 |
 | transform | 12 | 0 | 12 |
+| normalize | 11 | 0 | 11 |
 | stats | 17 | 0 | 17 |
 | table | 15 | 0 | 15 |
 | data | 21 | 0 | 21 |
@@ -33,4 +34,4 @@ _Generated by `lib/content/conformance.sh`_
 | md-import | 38 | 0 | 38 |
 | md-doc | 12 | 0 | 12 |
 | fed | 20 | 0 | 20 |
-| **Total** | **594** | **0** | **594** |
+| **Total** | **605** | **0** | **605** |