feat: add PostToolUse hook to auto-trigger readme-documentarian

Adds a Bash PostToolUse hook that detects the prek documentation audit
warning and injects additionalContext into Claude's session, prompting
it to invoke the readme-documentarian agent automatically.

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

.claude/hooks/doc-audit-trigger.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+# PostToolUse hook: detects the documentation audit warning from prek post-commit
+# hooks and injects a prompt for Claude to invoke the readme-documentarian agent.
+set -euo pipefail
+
+input=$(cat)
+
+stdout=$(echo "$input" | python3 -c "
+import sys, json
+try:
+    d = json.load(sys.stdin)
+    resp = d.get('tool_response', {})
+    if isinstance(resp, dict):
+        print(resp.get('stdout', ''))
+    else:
+        print(str(resp))
+except Exception:
+    pass
+")
+
+if echo "$stdout" | grep -q '\[Documentation Audit\].*documentation was not updated'; then
+    printf '{"additionalContext": "The post-commit documentation audit flagged that code changed but README.md was not updated. Invoke the readme-documentarian agent now to review the recent changes and update the documentation."}\n'
+fi

.claude/settings.json

@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": ".claude/hooks/doc-audit-trigger.sh"
+          }
+        ]
+      }
+    ]
+  }
+}