feat(provider): auto-detect Ollama on port 11434 #12

Summary

Automatically detect and configure Ollama if running on port 11434.

Problem

Users must manually configure Ollama, which is error-prone.

Related: anomalyco#5344, anomalyco#5160

Solution

On startup, check port 11434 for Ollama. If found and not configured, auto-create provider config.

Changes

• File: packages/opencode/src/provider/provider.ts
• Lines: ~20-30
• Risk: Low
• Dependencies: Requires PR #4a, #4b

Testing

• Test with Ollama running
• Test with Ollama not running
• Test with Ollama already configured