Fix gemini-cli E2E test: use GEMINI_API_KEY=dummy and --load Docker images

- gemini-cli requires auth to run `mcp list`; GOOGLE_GENAI_USE_GCA triggers
  an interactive OAuth flow. GEMINI_API_KEY=dummy satisfies the check without
  network access.
- Add --load to docker build commands so images are available to the daemon
  when using buildx container drivers.
- Pre-create /root/.gemini in the gemini-cli Dockerfile to avoid ENOENT
  on projects.json.

Author: danielealbano

Makefile

@@ -37,9 +37,9 @@ clean:
 
 # Build Docker images for E2E tests
 test-e2e-build:
-	docker build -t mcp-test-claude-code tests/docker/claude-code/
-	docker build -t mcp-test-cursor tests/docker/cursor/
-	docker build -t mcp-test-gemini-cli tests/docker/gemini-cli/
+	docker build --load -t mcp-test-claude-code tests/docker/claude-code/
+	docker build --load -t mcp-test-cursor tests/docker/cursor/
+	docker build --load -t mcp-test-gemini-cli tests/docker/gemini-cli/
 
 # Run E2E testcontainers tests (requires Docker)
 test-e2e: test-e2e-build

tests/docker/gemini-cli/Dockerfile

@@ -1,2 +1,2 @@
 FROM node:20-slim
-RUN npm install -g @google/gemini-cli
+RUN npm install -g @google/gemini-cli && mkdir -p /root/.gemini

tests/test_install_e2e.rs

@@ -100,7 +100,7 @@ async fn test_e2e_gemini_cli_recognizes_config() {
         InstallTarget::GeminiCli,
         "/root/.gemini/settings.json",
         vec!["gemini".to_string(), "mcp".to_string(), "list".to_string()],
-        vec![("GOOGLE_GENAI_USE_GCA", "true")],
+        vec![("GEMINI_API_KEY", "dummy")],
     )
     .await;
 }