Add HeXi bot codebase: custom plugins, web frontends, tests

- hexi core: message handling, rate limiting, cooldown, plugin manager
- Custom plugins: BF stats, daily check-in, quotes, persona cards, etc.
- Community plugins vendored under hexi/plugins with local fixes
- Web admin frontends (learning-chat, persona-admin), unified hexi/web
- Tests for rate_limit/cooldown/memes/persona; poetry.lock

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

requirements.txt

@@ -0,0 +1,21 @@
+nonebot2[fastapi]>=1.9
+
+chardet>=5.2.0
+websockets>=10.4
+httpx>=0.23.3
+pillow>=10.3.0
+playwright>=1.44.0
+requests>=2.32.3
+pilmoji>=2.0.4
+aiohttp>=3.9.5
+CairoSVG>=2.7.1
+qrcode>=7.4.2
+pydantic>=2.7.3
+mcstatus>=11.1.1
+SQLAlchemy>=2.0.30
+gradio_client>=1.4.0
+aiohttp-retry>=2.8.3
+
+# nonebot_plugin_group_daily_analysis
+ulid-py>=1.1.0
+diskcache>=5.6.3