chore: drop an AI vendor's tool directory from .prettierignore (closes #363)

.prettierignore listed an AI vendor's tool directory, the only such
name in the tree. The directory is not tracked, so the line ignored
nothing and removing it changes no formatting result.

Model: opus-5-5

.prettierignore

@@ -2,4 +2,3 @@ node_modules/
 yarn.lock
 dist/
 release/
-.claude/

TODO.md

@@ -45,6 +45,10 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-10-05: `.prettierignore` no longer lists an AI vendor's tool directory
+  ([#363](https://git.eeqj.de/sneak/AutistMask/issues/363)). The directory is
+  not tracked, so the line ignored nothing.
+
 - 2026-10-05: The Chrome end-to-end suite drives both ways the wait for a
   transaction's receipt ends on the error screen
   ([#315](https://git.eeqj.de/sneak/AutistMask/issues/315)): lookups that still