content: find-replace rewrites all text-bearing fields (756/756)

fr-rewrite dispatches per block type so image alt, list items, and table
headers/cells are renamed alongside text/heading/code/quote/callout —
matching exactly the set asText/stats/word-count fold into prose. Prior
find-replace skipped them, so a rename stayed visible in counts/exports.

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

lib/content/find-replace.sx

@@ -1,11 +1,17 @@
-;; content-on-sx — global find/replace across text-bearing blocks.
+;; content-on-sx — global find/replace across every text-bearing field.
 ;;
-;; Replaces every occurrence of `from` with `to` in the `text` field of
-;; text / heading / code / quote / callout blocks, tree-wide (via the transform
-;; layer). For renaming a term throughout a document. Immutable; case-sensitive.
-;; (Same text-bearing set asText/stats/summary treat as content.)
+;; Replaces every occurrence of `from` with `to` in the text-bearing fields of
+;; a document, tree-wide (via the transform layer):
+;;   - the `text` of text / heading / code / quote / callout blocks
+;;   - the `alt` of image blocks
+;;   - each item of list blocks
+;;   - every header and cell of table blocks
+;; This is exactly the set asText / stats / summary draw prose from, so a rename
+;; via content/find-replace and a word count over asText stay consistent.
+;; Immutable; case-sensitive.
 ;;
-;; Requires (loaded by harness): block.sx, transform.sx (content/map-blocks).
+;; Requires (loaded by harness): block.sx, transform.sx (content/map-blocks),
+;; table.sx (CtTable ivars).
 
 (define
   fr-in?
@@ -16,19 +22,54 @@
       ((= (first xs) x) true)
       (else (fr-in? x (rest xs))))))
 
+(define fr-rep (fn (s from to) (replace (str s) from to)))
+
+;; Blocks whose prose content find/replace rewrites (matches asText's set).
 (define
   fr-has-text?
   (fn
     (b)
-    (fr-in? (blk-type b) (list "text" "heading" "code" "quote" "callout"))))
+    (fr-in?
+      (blk-type b)
+      (list "text" "heading" "code" "quote" "callout" "image" "list" "table"))))
+
+;; Per-type field rewrite. Each branch returns a new (copy-on-write) block.
+(define
+  fr-rewrite
+  (fn
+    (b from to)
+    (let
+      ((t (blk-type b)))
+      (cond
+        ((= t "image")
+          (blk-set b "alt" (fr-rep (blk-get b "alt") from to)))
+        ((= t "list")
+          (let
+            ((items (blk-get b "items")))
+            (if
+              (list? items)
+              (blk-set b "items" (map (fn (it) (fr-rep it from to)) items))
+              b)))
+        ((= t "table")
+          (let
+            ((hs (blk-get b "headers")) (rs (blk-get b "rows")))
+            (let
+              ((b1 (if (list? hs) (blk-set b "headers" (map (fn (h) (fr-rep h from to)) hs)) b)))
+              (if
+                (list? rs)
+                (blk-set
+                  b1
+                  "rows"
+                  (map
+                    (fn
+                      (r)
+                      (if (list? r) (map (fn (c) (fr-rep c from to)) r) r))
+                    rs))
+                b1))))
+        (else (blk-set b "text" (fr-rep (blk-get b "text") from to)))))))
 
 (define
   content/find-replace
   (fn
     (doc from to)
-    (content/map-blocks
-      doc
-      fr-has-text?
-      (fn
-        (b)
-        (blk-set b "text" (replace (str (blk-get b "text")) from to))))))
+    (content/map-blocks doc fr-has-text? (fn (b) (fr-rewrite b from to)))))