fix: ChatBubble crash and DeepSeek API compatibility

- Fix ChatBubble to handle non-string content with String() wrapper
- Fix API route to use generateText for non-streaming requests
- Add @ai-sdk/openai-compatible for non-OpenAI providers (DeepSeek, etc.)
- Use Chat Completions API instead of Responses API for compatible providers
- Update ChatBubble tests and fix component exports to kebab-case
- Remove stale PascalCase ChatBubble.tsx file

.gitignore

@@ -46,10 +46,10 @@ next-env.d.ts
 # Project-specific: AI/Agent tools
 #/.agent/
 #/.claude/
-/_bmad/
+#/_bmad/
 
 # Project-specific: BMAD output (optional - uncomment to ignore)
-_bmad-output/
+#_bmad-output/
 
 # IDE
 .vscode/