Fix deterministic release with both CLI binaries

[regenrek]

Why

• adding the branded switchloom binary made unqualified cargo run calls ambiguous
• the release script must remain the only deterministic publication path

Change

• select the model-routing binary explicitly for both generated fixture commands

Verification

• bash -n scripts/release.sh
• git diff --check
• the previous release attempt failed before tag or push and left no external release state