fix nix develop command syntax in CI workflow

Use bash -c to properly execute cargo test commands within nix develop.
Previously, the quoted command string was treated as a single executable
name instead of being parsed as a command with arguments.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: Your Name

.github/workflows/test.yml

@@ -22,8 +22,8 @@ jobs:
           cache-directories: "server"
 
       - name: Run tests
-        run: cd server && nix develop --command "cargo test -- --test-threads=1"
+        run: cd server && nix develop --command bash -c "cargo test -- --test-threads=1"
 
       - name: Run tests with output
-        run: cd server && nix develop --command "cargo test -- --nocapture --test-threads=1"
+        run: cd server && nix develop --command bash -c "cargo test -- --nocapture --test-threads=1"
         if: failure()