The durable tests and preflight fail to link on Apple silicon #616

Expected. On an Apple silicon Mac, a Module durable test and ./lyracore preflight link with no extra flags, as they do on Linux.

Actual (at 87109e3c). The Module builds as both cdylib and rlib (module/Cargo.toml#L12-L13). On a host build the cdylib leaves the SpacetimeDB host imports undefined. The Linux linker accepts that in a shared library; the macOS linker refuses it. .cargo/config.toml sets flags only for wasm32-unknown-unknown. The workaround agents used on #612 and #614 is not written down:

--config 'target.aarch64-apple-darwin.rustflags=["-C","link-arg=-undefined","-C","link-arg=dynamic_lookup"]'

How it shows. A contributor on a Mac gets a link error on a clean checkout and cannot run the durable suite or preflight. Linux and CI are not affected.

Fix direction. Emit cargo:rustc-cdylib-link-arg=-undefined and dynamic_lookup from the Module build script when the target is macOS. That flag reaches only the cdylib, so the Gateway keeps its normal link errors. If that fails, document the workaround where the durable tests are described.