v0.18.1 — scaffold template pin patch

Patch release on top of v0.18.0.

What was wrong

The bundled rustio startproject template (crates/rustio-admin-cli/templates/project/Cargo.toml.tmpl) pinned rustio-admin = "0.16.0" through three workspace releases (0.17.0, 0.17.1, 0.18.0) that bumped the framework but missed the template. 0.16.0 was never published to crates.io either (latest published: 0.13.0), so any fresh rustio startproject hit a registry resolve failure:

error: no matching package found
searched package name: `rustio-admin`
versions found: 0.13.0, 0.12.0, ...
required by package `my-project v0.1.0`

The fix

The template now reads rustio-admin = "0.18.1", matching the workspace minor. Per the CLAUDE.md convention: bundled template pin matches released framework (the 0.2.1 lesson).

-rustio-admin = "0.16.0"
+rustio-admin = "0.18.1"

How it was found

During local verification of the v0.18.0 engine-generated colors.css render — scaffolding a fresh project with rustio startproject verify_engine produced a Cargo.toml that wouldn't cargo build against any registry version.

Recommendation

The release checklist should touch both the workspace Cargo.toml and crates/rustio-admin-cli/templates/project/Cargo.toml.tmpl, or a CI grep guard should compare the two. The pin drift was silent across three releases.

Compatibility

• No library API change.
• No CLI surface change.
• Drop-in upgrade from 0.18.0 for the framework itself.
• For rustio startproject users: previously you had to hand-edit the generated Cargo.toml after every scaffold. After 0.18.1, fresh scaffolds work as long as rustio-admin = "0.18.1" exists in your registry (local [patch.crates-io] continues to work in either case).