Fix CI workflow and hook validation

src/hooks.py

@@ -1,5 +1,3 @@
-"""Git hook integration for prepare-commit-msg."""
-
 import os
 import shutil
 from dataclasses import dataclass
@@ -87,6 +85,19 @@ exec commit-gen hook "$@"
         try:
             hook_path = self.get_hook_path()
 
+            if not self.repo_path.exists():
+                return HookResult(
+                    success=False,
+                    message=f"Repository path does not exist: {self.repo_path}"
+                )
+
+            git_dir = self.repo_path / ".git"
+            if not git_dir.exists():
+                return HookResult(
+                    success=False,
+                    message=f"Git directory not found: {git_dir}. Are you in a git repository?"
+                )
+
             if not self.hooks_dir.exists():
                 return HookResult(
                     success=False,