Support passing configuration via envoirment values for SSE

[mbaitelman]

Im running the server with the SSE mode and each request is failing.
I see that stdio mode works with env vars https://github.com/akuity/argocd-mcp/blob/4114f499f05614e88dce72ca60409c538ad4f04d/src/server/transport.ts#L7 but server mode doesn't https://github.com/akuity/argocd-mcp/blob/4114f499f05614e88dce72ca60409c538ad4f04d/src/server/transport.ts#L22

My use case for this is to run the MCP server with SSE and a web chat UI, rather than requiring folks to use a MCP compatible IDE.

[deanchanter]

Need this for http as well