Fix Codex PreToolUse hook failing on Windows

Replace bash-only [ -f ] file check with a cross-platform Python one-liner
so the hook works on Windows where cmd.exe has no [ builtin.

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

graphify/__main__.py

@@ -718,10 +718,14 @@ _CODEX_HOOK = {
                 "hooks": [
                     {
                         "type": "command",
+                        # Use Python for the file check so the hook works on Windows
+                        # (cmd.exe has no [ -f ] builtin; Python is always available).
                         "command": (
-                            "[ -f graphify-out/graph.json ] && "
-                            r"""echo '{"hookSpecificOutput":{"hookEventName":"PreToolUse","additionalContext":"graphify: Knowledge graph exists. Read graphify-out/GRAPH_REPORT.md for god nodes and community structure before searching raw files."}}' """
-                            "|| true"
+                            "python3 -c \""
+                            "import pathlib,json,sys; "
+                            "p=pathlib.Path('graphify-out/graph.json'); "
+                            r"print(json.dumps({'hookSpecificOutput':{'hookEventName':'PreToolUse','additionalContext':'graphify: Knowledge graph exists. Read graphify-out/GRAPH_REPORT.md for god nodes and community structure before searching raw files.'}})) if p.exists() else None"
+                            "\""
                         ),
                     }
                 ],