#13539: Claude/update dockerfile cmd 1 te te

<!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates the Docker image default `CMD` to run the built gateway entrypoint (`dist/index.js`) and binds the gateway to `0.0.0.0` for container hosting. It also modifies the Render blueprint (`render.yaml`) by changing the service plan tier. These changes affect how the gateway starts inside Docker/Render and how Render provisions the service. <h3>Confidence Score: 3/5</h3> - Not safe to merge as-is; deploy will likely fail on Render due to port mismatch. - The Dockerfile change hard-codes a port that conflicts with the Render-provided PORT env var in render.yaml, which will prevent traffic/health checks from reaching the service. The Render plan change is also an unrelated behavioral/cost change that should be addressed before merging. - Dockerfile, render.yaml <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} <!-- /greptile_comment -->