chore(gitignore): exclude repo-root test scratch + DDL-bug macro filenames

Two sources of cruft kept showing up in `git status` after running
FiveSql2 tests from the repo directory:

  1. Scratch tables from standalone bench PRGs (t.dbf, b.dbf, s.dbf,
     p.dbf). Anchored to root only so tracked fixtures in subdirs
     (area_a.dbf, customers.dbf, idxadv.dbf, ...) stay unaffected.

  2. Literal filenames like `Lower(cTable) + "_pk.ntx".ntx` — this
     is a FiveSql2 DDL bug where a macro-substituted index filename
     fails to evaluate and ends up as the actual filename. Ignoring
     the `Lower*.ntx`/`Lower*.cdx` pattern keeps the garbage out of
     commits. The underlying DDL bug needs a separate fix.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -31,3 +31,17 @@ vendor/
 
 # Reference projects (not part of Five source)
 ref/
+
+# Ad-hoc test scratch at repo root.
+# Existing tracked DBF fixtures (area_a.dbf, customers.dbf, idxadv.dbf, ...)
+# remain tracked. These patterns keep new scratch tables out of the index
+# when tests are accidentally run from the repo directory.
+/t.dbf
+/b.dbf
+/s.dbf
+/p.dbf
+# Macro-unexpanded index filenames — signature of a FiveSql2 DDL bug where
+# `Lower(cTable) + "_pk.ntx"` ends up as a literal filename. Keep the
+# garbage out of commits; file a real bug to fix the DDL path.
+Lower*.ntx
+Lower*.cdx