Simplify install with one-click scripts; honor HTTP(S)_PROXY for Telegram.

Add install.ps1/install.sh, shrink README to script-first flow, register bot commands, and route API calls through undici EnvHttpProxyAgent when a proxy is set (v0.2.2).

Co-authored-by: Cursor <cursoragent@cursor.com>

examples/telegram-agent/cordis.patch.example.yml

@@ -1,6 +1,5 @@
-- insert:
-    - id: dsh-telegram-channel
-      name: dsh-telegram-channel
-      config:
-        token: ''
-        allowedUserIds: [123456789]
+# 插件安装时已自动 insert。用户 patch 只需按 id 覆盖 config（不要再 insert 同名 id）。
+- id: dsh-telegram-channel
+  config:
+    token: ''
+    allowedUserIds: [123456789]