fix: remove trailing blank line from governance.md

The end-of-file-fixer pre-commit hook requires files to end with
exactly one newline. governance.md had an extra trailing blank line.

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

.claude/governance.md

@@ -63,4 +63,3 @@ Do not:
 - Do not catch bare `Exception` — catch specific exceptions
 - Do not use mutable default arguments (e.g., `def f(x=[])`)
 - Do not use `import *` — use explicit imports
-