Switch shared Ollama Granite entries to Granite 4 (#9)

* Remove granite-bridge references from Ollama config

Keep the shared OpenCode config project-agnostic while preserving local Ollama models via Ollama's default local endpoint.

* Switch shared Ollama Granite entries to Granite 4

Keep the global Ollama model list aligned with Granite 4 releases while removing legacy Granite variants from the shared config.