fix: use Codex hooks schema (nested structure, timeout in seconds, matcher groups)

Author: blackwell-systems

hooks/hooks.json

@@ -1,14 +1,28 @@
 {
-  "hooks": [
-    {
-      "event": "SessionStart",
-      "command": "rm -f /tmp/gcf-proxy-stats.json",
-      "timeout": 1000
-    },
-    {
-      "event": "Stop",
-      "command": "node -e \"const fs=require('fs'); try{const d=JSON.parse(fs.readFileSync('/tmp/gcf-proxy-stats.json','utf8')); if(d.calls>0){const s=d.pct_saved.toFixed(0); const tb=d.est_tokens_saved; const saved=tb>=1000?(tb/1000).toFixed(1)+'K':tb; console.log(JSON.stringify({notification:'gcf-proxy: '+d.calls+' tool calls rewritten, '+s+'% fewer tokens (~'+saved+' tokens saved)'}))}}catch(e){}\"",
-      "timeout": 1000
-    }
-  ]
+  "hooks": {
+    "SessionStart": [
+      {
+        "matcher": "startup|resume",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "rm -f /tmp/gcf-proxy-stats.json",
+            "timeout": 2
+          }
+        ]
+      }
+    ],
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "node -e \"const fs=require('fs'); try{const d=JSON.parse(fs.readFileSync('/tmp/gcf-proxy-stats.json','utf8')); if(d.calls>0){const s=d.pct_saved.toFixed(0); const tb=d.est_tokens_saved; const saved=tb>=1000?(tb/1000).toFixed(1)+'K':tb; console.log(JSON.stringify({notification:'gcf-proxy: '+d.calls+' tool calls rewritten, '+s+'% fewer tokens (~'+saved+' tokens saved)'}))}}catch(e){}\"",
+            "timeout": 2,
+            "statusMessage": "Checking GCF proxy savings"
+          }
+        ]
+      }
+    ]
+  }
 }