chore: exclude vendored site assets from the code-intelligence index

.cbmignore is not a gitignore — everything it lists stays tracked, shipped and
required at runtime. It only keeps site/assets/ out of the codebase-memory
knowledge graph: the minified asciinema-player bundle contributes hundreds of
single-letter symbols ($, $A, $e, $t, ...) that outrank real source in
full-text search, and no structural query about this codebase should resolve
into third-party minified output.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: trs-80

.cbmignore

@@ -0,0 +1,13 @@
+# Exclusions for the codebase-memory knowledge graph only.
+#
+# This file is NOT a gitignore. Everything listed here is tracked, shipped, and
+# required at runtime — it simply has no business in a code-intelligence index.
+# Syntax is gitignore syntax; the indexer reads .gitignore, .git/info/exclude
+# and this file.
+
+# Vendored asciinema-player bundle and the demo recording assets for the landing
+# page. The minified bundle alone contributes hundreds of single-letter symbols
+# ($, $A, $e, $t, ...) that outrank real source in BM25 full-text search, and no
+# structural query about this codebase should ever resolve into third-party
+# minified output. Regenerated by scripts/record-demo.sh, never hand-edited.
+site/assets/