fix: distinguish an unknown holder count from zero so a legitimate token is not filtered (closes #230)

TODO.md

@@ -44,6 +44,10 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-12: An unreported `holders_count` is now parsed as `null` rather than
+  `0`, so the low-holder rule declines to judge an unknown count instead of
+  hiding a legitimate token as spam, in both the transaction history and the
+  Send token selector ([#230](https://git.eeqj.de/sneak/AutistMask/issues/230)).
 - 2026-08-12: Bundled token list documentation no longer states a count. The
   four "top 250" claims in `README.md` and the "roughly 500" claim in
   `docs/README.md` are replaced with a description of how the list is actually