feat(ai): Implement Gemini provider with streaming and tool support

- Added GeminiLLM provider implementation with GoogleGenerativeAI SDK
- Supports streaming with text/thinking content and completion signals
- Handles Gemini's parts-based content system (text, thought, functionCall)
- Implements tool/function calling with proper format conversion
- Maps between unified types and Gemini-specific formats (model vs assistant role)
- Added test example matching other provider patterns
- Fixed typo in AssistantMessage type (stopResaon -> stopReason) across all providers

package-lock.json

@@ -654,6 +654,15 @@
 				}
 			}
 		},
+		"node_modules/@google/generative-ai": {
+			"version": "0.24.1",
+			"resolved": "https://registry.npmjs.org/@google/generative-ai/-/generative-ai-0.24.1.tgz",
+			"integrity": "sha512-MqO+MLfM6kjxcKoy0p1wRzG3b4ZZXtPI+z2IE26UogS2Cm/XHO+7gGRBh6gcJsOiIVoH93UwKvW4HdgiOZCy9Q==",
+			"license": "Apache-2.0",
+			"engines": {
+				"node": ">=18.0.0"
+			}
+		},
 		"node_modules/@mariozechner/ai": {
 			"resolved": "packages/ai",
 			"link": true
@@ -1604,6 +1613,7 @@
 			"dependencies": {
 				"@anthropic-ai/sdk": "0.60.0",
 				"@google/genai": "1.14.0",
+				"@google/generative-ai": "^0.24.1",
 				"chalk": "^5.5.0",
 				"openai": "5.12.2"
 			},