Replace Ollama with llama-server (OpenAI-compatible API)

- Update llm.py to use OpenAI client with custom base_url for llama-server
- Update agents.py to use ChatOpenAI instead of ChatOllama
- Remove unused ollama imports from main.py, chunker.py, query.py
- Add LLAMA_SERVER_URL and LLAMA_MODEL_NAME env vars
- Remove ollama and langchain-ollama dependencies

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

main.py

@@ -5,7 +5,6 @@ import os
 import sqlite3
 import time
 
-import ollama
 from dotenv import load_dotenv
 
 import chromadb
@@ -17,11 +16,6 @@ from utils.request import PaperlessNGXService
 
 _dotenv_loaded = load_dotenv()
 
-# Configure ollama client with URL from environment or default to localhost
-ollama_client = ollama.Client(
-    host=os.getenv("OLLAMA_URL", "http://localhost:11434"), timeout=10.0
-)
-
 client = chromadb.PersistentClient(path=os.getenv("CHROMADB_PATH", ""))
 simba_docs = client.get_or_create_collection(name="simba_docs2")
 feline_vet_lookup = client.get_or_create_collection(name="feline_vet_lookup")