fix(hub-guide): correct hooks.json format and remove redundant manifest field

- hooks.json needs 'hooks' wrapper key at top level
- Remove 'hooks' field from plugin.json (auto-discovered from hooks/hooks.json)
- Simplify hook entries (no nested hooks array)

hooks/hooks.json

@@ -1,17 +1,15 @@
 {
-  "SessionStart": [{
-    "hooks": [{
+  "hooks": {
+    "SessionStart": [{
       "type": "command",
       "command": "bash \"$CLAUDE_PLUGIN_ROOT/hooks/scripts/detect-project.sh\"",
       "timeout": 10
-    }]
-  }],
-  "PreToolUse": [{
-    "matcher": "Write|Edit",
-    "hooks": [{
+    }],
+    "PreToolUse": [{
+      "matcher": "Write|Edit",
       "type": "command",
       "command": "bash \"$CLAUDE_PLUGIN_ROOT/hooks/scripts/detect-file-type.sh\" \"$TOOL_INPUT\"",
       "timeout": 10
     }]
-  }]
+  }
 }