docs: usar URL assinada do CDN para o modelo Llama 3.2 3B

O link resolve do Hugging Face não baixa o GGUF. Os comandos wget
agora apontam para o CDN com -O e aspas, para o shell não quebrar nos &.

README.md

@@ -134,7 +134,7 @@ cd backend
 mkdir -p models
 
 # Baixe o modelo Llama 3.2 3B quantizado
-wget https://huggingface.co/MaziyarPanahi/Llama-3.2-3B-Instruct-GGUF/resolve/main/llama-3.2-3b-instruct-q4_0.gguf
+wget -O llama-3.2-3b-instruct-q4_0.gguf "https://us.aws.cdn.hf.co/xet-bridge-us/6718a700b21019fade8d68ac/b472da725da9aaf0e050c885680a67f61fceb097eb4277b0cc1e0b94e3559345?user_id=public&xip=4ii5zzvItH8&X-Xet-Cas-Uid=public&response-content-disposition=attachment%3B+filename*%3DUTF-8%27%27llama-3.2-3b-instruct-q4_0.gguf%3B+filename%3D%22llama-3.2-3b-instruct-q4_0.gguf%22%3B&Expires=1793546619&Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly91cy5hd3MuY2RuLmhmLmNvL3hldC1icmlkZ2UtdXMvNjcxOGE3MDBiMjEwMTlmYWRlOGQ2OGFjL2I0NzJkYTcyNWRhOWFhZjBlMDUwYzg4NTY4MGE2N2Y2MWZjZWIwOTdlYjQyNzdiMGNjMWUwYjk0ZTM1NTkzNDVcXD91c2VyX2lkPXB1YmxpYyZ4aXA9NGlpNXp6dkl0SDgmWC1YZXQtQ2FzLVVpZD1wdWJsaWMmcmVzcG9uc2UtY29udGVudC1kaXNwb3NpdGlvbj1hdHRhY2htZW50JTNCK2ZpbGVuYW1lJTJBJTNEVVRGLTglMjclMjdsbGFtYS0zLjItM2ItaW5zdHJ1Y3QtcTRfMC5nZ3VmJTNCK2ZpbGVuYW1lJTNEJTIybGxhbWEtMy4yLTNiLWluc3RydWN0LXE0XzAuZ2d1ZiUyMiUzQiIsIkNvbmRpdGlvbiI6eyJEYXRlTGVzc1RoYW4iOnsiRXBvY2hUaW1lIjoxNzkzNTQ2NjE5fX19XX0_&Signature=MEUCIBdL2cMsOqav%7EbG9Q2mearSLUBdBtfCA3sOBE5GdbXUnAiEA7xWOea%7ETy0Jf%7EPgRYyx1S9bxvnSFoTBI%7ERadl-Nmd8E_&Key-Pair-Id=01KXEF4KZ1B6FV465MAWR4M21F&Hash-Algorithm=SHA256"
 mv llama-3.2-3b-instruct-q4_0.gguf models/
 
 # Ou use o GPT4All para baixar automaticamente