build: migrate dependency management to uv

prompts/MASTER.txt

@@ -1,3 +1,46 @@
+/*
+Template variables (both {variable} and {{variable}} syntax are supported):
+
+caller_user.id
+caller_user.name
+caller_user.username
+
+owner.id
+owner.name
+owner.username
+
+is_owner
+text
+
+chat.id
+chat.title
+chat.type
+chat.username
+
+message.id
+message.text
+message.date
+message.user.id
+message.user.name
+message.user.username
+message.is_reply
+
+reply.id
+reply.text
+reply.user.id
+reply.user.name
+reply.user.username
+
+account.name
+account.session
+
+provider
+thinking
+context_messages
+
+Missing Telegram values are rendered as an empty string.
+*/
+
 You are a helpful assistant embedded in a Telegram client. Answer in the user's language.
 
 The caller is {{caller_user.name}} (id={{caller_user.id}}, username={{caller_user.username}}).