Implement ID-based routing and folder auto-generation from titles

Major features:
- Switch from slug-based to ID-based routing (/documents/123)
- Enable title editing with automatic slug/path regeneration
- Auto-generate folder structure from title slashes (e.g., Laravel/Livewire/Components)
- Persist sidebar folder open/close state using localStorage
- Remove slug unique constraint (ID routing makes it unnecessary)
- Implement recursive tree view with multi-level folder support

Architecture changes:
- DocumentService: Add generatePathAndSlug() for title-based path generation
- Routes: Change from {document:slug} to {document} for ID binding
- SidebarTree: Extract recursive rendering to partials/tree-item.blade.php
- Database: Remove unique constraint from documents.slug column

UI improvements:
- Display only last path component in sidebar (Components vs Laravel/Livewire/Components)
- Folder state persists across page navigation via localStorage
- Title field accepts slashes for folder organization

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

docker/mysql/my.cnf

@@ -0,0 +1,23 @@
+[mysqld]
+# 文字コード設定
+character-set-server = utf8mb4
+collation-server = utf8mb4_unicode_ci
+
+# タイムゾーン設定
+default-time-zone = '+09:00'
+
+# ログ設定
+general_log = 0
+slow_query_log = 1
+slow_query_log_file = /var/log/mysql/slow-query.log
+long_query_time = 2
+
+# パフォーマンス設定
+max_connections = 100
+max_allowed_packet = 64M
+
+[client]
+default-character-set = utf8mb4
+
+[mysql]
+default-character-set = utf8mb4