feat(falcon-rate): WASI-free component + through-wasm closed-loop proof

[avrabe]

The falcon-rate worked example for the jess consumption contract (jess#167). Verify-before-build paid off: the real typed seam already existed (falcon:cascade rate.tick(vehicle-state, rate-setpoint) -> torque-setpoint, wrapping RatePid) and a native closed-loop convergence test already existed (rate_p03). Two things were genuinely missing.

1. WASI-free build (so it lowers to bare metal)

The cargo-component build pulled std (via thread_local!) → 10 WASI imports, which don't lower to the M4/M7/F100 targets (synth → gale). Converted the component to no_std on the cargo-component path — single-threaded statics instead of thread_local!, lol_alloc global allocator, panic handler — all gated to not(feature = "bazel-bindings") so the Bazel/std path is untouched.

Result — imports drop from 10 (incl. all WASI) to one:

world root {
  import falcon:cascade/types@0.7.0;   // type-only
  export falcon:cascade/rate@0.7.0;
}

A pure transformer that lowers cleanly and a WASI-less host can drive directly. (Thanks to the "you can do this without WASI" steer.)

2. Loop-complete proof THROUGH the wasm seam

tests/rate-loop-proof is a minimal WASI-less wasmtime host that closes the control loop across the real WIT boundary: plant (ω̇ = τ/I) → gyro into vehicle-state → rate.tick → torque → plant. Locally:

through-wasm closed loop: omega_x -> 1.0059 rad/s (target 1.0), |err| = 0.0059
PASS: converged at 0.193s, steady-state |err| 0.0059 < 0.01 — loop closes through the component

That's "always complete loop," proven through the component exactly as jess will run it — not an open-loop stub, not an internal sealed demo.

Scope / follow-ups

• No change to the Bazel/std build path (gating verified; the standalone cargo build default-feature error is pre-existing — falcon_rate_bindings is Bazel-provided).
• Follow-ups (separate): wire the proof as a CI gate; per-component OCI publish (jess#167 decision 5) — the thing that lets jess wkg oci pull falcon-rate.

Refs: jess#167 (consumption contract).

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