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>

hexi/plugins/nonebot_plugin_group_tools/constants.py

@@ -0,0 +1,16 @@
+from pathlib import Path
+
+# 插件根目录(放 dk_is_me.jpg 等根级资源)
+PLUGIN_ROOT = Path(__file__).resolve().parent
+IMG_DIR = PLUGIN_ROOT
+# 资源目录:res/ 下的 record/ 与 img/
+RES_DIR = PLUGIN_ROOT / "res"
+# 视频临时目录(项目数据目录下)
+TEMP_DIR = PLUGIN_ROOT.parents[1] / "data" / "temp"
+
+# 违禁词(触发黑手语音)
+BANNED_WORDS = (
+    "rbq", "RBQ", "憨批", "废物", "死妈", "崽种", "傻逼", "傻逼玩意",
+    "没用东西", "傻B", "傻b", "SB", "sb", "煞笔", "cnm", "爬", "kkp",
+    "nmsl", "D区", "口区", "我是你爹", "nmbiss", "弱智", "给爷爬", "杂种爬", "爪巴",
+)