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/tests/query.sx

@@ -1,8 +1,11 @@
-;; Extension — block query + table of contents.
+;; Extension — block query + table of contents + prose search.
 
 (st-bootstrap-classes!)
 (content/bootstrap!)
+(content-bootstrap-text!)
 (content-bootstrap-section!)
+(content-bootstrap-table!)
+(content-bootstrap-callout!)
 
 (define
   d
@@ -87,3 +90,49 @@
   "deep toc level"
   (get (first (content/headings deep)) :level)
   3)
+
+;; ── prose search (content/search-text) ──
+;; "cat" appears in text, image alt, a list item, a table cell, and a callout
+;; — every text-bearing field — so search must find all five via asText.
+(define
+  sd
+  (doc-append
+    (doc-append
+      (doc-append
+        (doc-append
+          (doc-append
+            (doc-empty "sd")
+            (mk-heading "sh" 1 "Welcome aboard"))
+          (mk-text "st" "the cat sat"))
+        (mk-image "si" "/x.png" "a cat photo"))
+      (mk-list "sl" false (list "first cat" "second dog")))
+    (mk-section
+      "sec"
+      (list
+        (mk-table "stb" (list "Animal") (list (list "cat") (list "fish")))
+        (mk-callout "sc" "note" "beware of cat")))))
+
+(content-test
+  "search across every text-bearing field"
+  (content/search-text-ids sd "cat")
+  (list "st" "si" "sl" "stb" "sc"))
+(content-test "search count" (len (content/search-text sd "cat")) 5)
+(content-test
+  "search heading text"
+  (content/search-text-ids sd "Welcome")
+  (list "sh"))
+(content-test
+  "search list item only"
+  (content/search-text-ids sd "dog")
+  (list "sl"))
+(content-test "search no match" (content/search-text-ids sd "zzz") (list))
+;; section containers are excluded — a term living only inside a section's
+;; children returns the child, never the section wrapper.
+(content-test
+  "search excludes section wrapper"
+  (content/search-text-ids sd "fish")
+  (list "stb"))
+(content-test
+  "search returns block objects"
+  (blk-id (first (content/search-text sd "Welcome")))
+  "sh")