Connect to Discord, switch to NVIDIA NIM providers

- Enable Discord channel, respond to all messages from allowed users
- Switch all agents to NVIDIA NIM (Kimi K2.5, DeepSeek V3.1)
- Auto-approve all tools for non-interactive Docker deployment
- Fix tool call arguments serialization (dict → JSON string)
- Fix Dockerfile to copy source before uv sync

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

agents/coder.md

@@ -1,7 +1,7 @@
 ---
 name: coder
-provider: anthropic
-model: claude-sonnet-4-5-20250929
+provider: kimi
+model: nvidia_nim/moonshotai/kimi-k2.5
 temperature: 0.3
 max_iterations: 30
 tools: