feat(claude-code): add project settings and commands

- Add .claude/settings.json with permissions and hooks
- Add /format-lessons slash command
- Add .claude/settings.local.json to .gitignore

.claude/commands/format-lessons.md

@@ -0,0 +1,8 @@
+Format all lesson JSON files including localized versions.
+
+Run prettier on all lesson files:
+```bash
+npx prettier --write "lessons/**/*.json"
+```
+
+This formats both root lessons (`lessons/*.json`) and localized lessons (`lessons/ar/`, `lessons/de/`, `lessons/es/`, `lessons/pl/`, `lessons/uk/`).

.claude/settings.json

@@ -0,0 +1,29 @@
+{
+	"permissions": {
+		"allow": [
+			"Bash(git add:*)",
+			"Bash(git commit:*)",
+			"Bash(git push:*)",
+			"Bash(npm run build:*)",
+			"Bash(grep:*)",
+			"Bash(npm run format.lessons:*)",
+			"Bash(xargs:*)",
+			"Bash(cat:*)",
+			"Bash(prettier --write:*)"
+		],
+		"deny": ["Read(./.env)", "Read(./.env.*)", "Read(./secrets/**)"]
+	},
+	"hooks": {
+		"PostToolUse": [
+			{
+				"matcher": "Write(lessons/**/*.json)",
+				"hooks": [
+					{
+						"type": "command",
+						"command": "npm run format.lessons 2>/dev/null || true"
+					}
+				]
+			}
+		]
+	}
+}

.gitignore

@@ -2,4 +2,7 @@
 .code
 node_modules
 dist
-coverage
+coverage
+
+# Claude Code local settings (user-specific)
+.claude/settings.local.json