fix(ci): hypatia mix project is at repo root, not scanner/ subdir

The hypatia repo has mix.exs at root level, not inside a scanner/
subdirectory. Remove the erroneous cd scanner step.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/hypatia-scan.yml

@@ -41,10 +41,9 @@ jobs:
           cd "$HOME/hypatia"
           if [ ! -f hypatia-v2 ]; then
             echo "Building hypatia-v2 scanner..."
-            cd scanner
             mix deps.get
             mix escript.build
-            mv hypatia ../hypatia-v2
+            mv hypatia hypatia-v2 || true
           fi
 
       - name: Run Hypatia scan