Increase model pull retry delay and attempts

Raised the base delay for model pull retries from 1s to 3s and updated log output to show seconds instead of milliseconds. Also increased the number of retries for model pull in integration tests from 3 to 5 to improve robustness.

src/test/java/io/github/ollama4j/integrationtests/OllamaAPIIntegrationTest.java

@@ -75,7 +75,7 @@ class OllamaAPIIntegrationTest {
         }
         api.setRequestTimeoutSeconds(120);
         api.setVerbose(true);
-        api.setNumberOfRetriesForModelPull(3);
+        api.setNumberOfRetriesForModelPull(5);
     }
 
     @Test