Fastly: missing edgezero_runtime_env warning is emitted before logger init and never reaches Fastly logs

[aram356]

Found in review of #351 (thread on lib.rs:144).

runtime_env_config runs before init_logger in run_app_with_request_extensions, so the log::warn! in its missing-store arm fires with no global logger installed and is a no-op. Compute@Edge hands out a fresh Wasm instance per request, so no later request sees it either. The warning's own text points operators at their Fastly logs to spot the gap, but it never reaches them.

A fix means resolving logging config before the env-store read, or deferring the warning until after init_logger. Pre-existing behavior; out of scope for #351.