content: in-document prose search via asText (763/763)

content/search-text + search-text-ids find every block whose (asText b)
contains a term — spanning all text-bearing fields by reusing the canonical
asText projection, so it can't drift from stats/find-replace. Section
wrappers excluded. +7 query tests.

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

lib/content/scoreboard.md

@@ -18,7 +18,7 @@ _Generated by `lib/content/conformance.sh`_
 | tree-edit | 17 | 0 | 17 |
 | move | 11 | 0 | 11 |
 | clone | 10 | 0 | 10 |
-| query | 13 | 0 | 13 |
+| query | 20 | 0 | 20 |
 | toc | 8 | 0 | 8 |
 | anchor | 6 | 0 | 6 |
 | outline | 14 | 0 | 14 |
@@ -45,4 +45,4 @@ _Generated by `lib/content/conformance.sh`_
 | md-import | 38 | 0 | 38 |
 | md-doc | 12 | 0 | 12 |
 | fed | 20 | 0 | 20 |
-| **Total** | **756** | **0** | **756** |
+| **Total** | **763** | **0** | **763** |