Specifies the concrete steps needed to replace the current READY stub
with real Wasm module execution:
- Optional cargo feature gate (wasmtime-runtime) to keep default builds
fast; production service unit uses the feature-enabled binary.
- Engine + Module setup from wasm file path.
- WasiCtxBuilder with inherited stdout/stderr for READY signal passthrough.
- READY signal timing: Option A (print before _start) vs Option B
(explicit weft_ready() export); Option A is the initial implementation.
- Entry point: _start (standard wasm32-wasi target output).
- Error handling: module load failures, trap handling, missing _start.
- Explicit non-scope: host imports beyond WASI, memory caps, component
model, Wasm threads, fuel metering.
- Prerequisite: confirmed wasm32-wasi app SDK before integration.
