Fix image limits test to use realistic payload sizes

Previous test used compressed 8k images (0.01MB) which was meaningless.
Now tests with actual large noise images that don't compress.

Realistic payload limits discovered:
- Anthropic: 6 x 3MB = ~18MB total (not 32MB as documented)
- OpenAI: 2 x 15MB = ~30MB total
- Gemini: 10 x 20MB = ~200MB total (very permissive)
- Mistral: 4 x 10MB = ~40MB total
- xAI: 1 x 20MB (strict request size limit)
- Groq: 5 x 5760px images (5 image + pixel limit)
- zAI: 2 x 15MB = ~30MB (50MB request limit)
- OpenRouter: 2 x 5MB = ~10MB total

Also fixed GEMINI_API_KEY env var (was GOOGLE_API_KEY).

Related to #120

packages/coding-agent/src/modes/interactive/components/tool-execution.ts

@@ -44,7 +44,7 @@ export class ToolExecutionComponent extends Container {
 	private args: any;
 	private expanded = false;
 	private showImages: boolean;
-	private isPartial = false;
+	private isPartial = true;
 	private result?: {
 		content: Array<{ type: string; text?: string; data?: string; mimeType?: string }>;
 		isError: boolean;