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>

plugin_template/nonebot_plugin_template/services/main.py

@@ -0,0 +1,20 @@
+"""业务逻辑层：一个业务动作一个方法；不依赖 nonebot(可单测)。"""
+
+from __future__ import annotations
+
+from hexi.web_config import get_effective_value
+
+from ..repository import get_record, save_record
+
+_PLUGIN_ID = __package__.rsplit(".", 1)[0]
+
+
+async def do_something(text: str) -> str:
+    """示例业务：记录输入并返回带配置的回复。"""
+    save_record("last_input", text)
+
+    prefix = get_effective_value(_PLUGIN_ID, "reply", "你好，我是模板插件！")
+    record = get_record("last_input")
+    if record:
+        return f"{prefix} 已记录：{record}"
+    return prefix