Add PostToolUse hook for auto-formatting Python with uvx black

- New hooks/format-code.sh: reads file path from stdin JSON, dispatches
  by extension (*.py → uvx black, *.js/ts → prettier)
- Updated settings.json: PostToolUse hook on Edit/Write/MultiEdit

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

hooks/format-code.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# Read tool input from stdin (JSON with tool_input.file_path)
+FILE=$(jq -r '.tool_input.file_path // empty' 2>/dev/null)
+
+[ -z "$FILE" ] && exit 0
+
+case "$FILE" in
+  *.py)
+    uvx black --quiet "$FILE" ;;
+  *.js|*.ts|*.jsx|*.tsx)
+    prettier --write "$FILE" 2>/dev/null ;;
+esac

settings.json

@@ -103,6 +103,18 @@
   },
   "effortLevel": "medium",
   "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Edit|Write|MultiEdit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "/home/cal/.claude/hooks/format-code.sh",
+            "timeout": 10
+          }
+        ]
+      }
+    ],
     "SessionEnd": [
       {
         "hooks": [