chore: improve CI cache reuse and build ordering

[itsyaasir]

Description of change

CI discards restored release artifacts on Linux and builds Rust before Move publication changes the lockfiles watched by the Rust build scripts. This preserves release artifacts and builds against the final Move inputs so subsequent tests and examples can reuse them.

• Upgrade the pinned Linux sccache from v0.2.15 to v0.17.0 and log the installed version.
• Restrict feature-check cleanup to cargo clean --profile dev.
• Run the release build after Move testing and publication, retaining platform coverage and single-threaded sandbox tests.

Links to any relevant issues

Part of #340. Further CI optimization and measurement remain open.

Type of change

• Bug fix (a non-breaking change which fixes an issue)

How the change has been tested

• YAML and Bash syntax checks; git diff --check.
• Verified publication precedes the unconditional release build and tests remain single-threaded.
• An isolated Cargo reproduction using the same lockfile watch directive rebuilt after a Move.lock change and reused artifacts when that change preceded the build. This does not establish the full CI timing improvement.
• Full workflow validation is pending CI. Compare the initial and repeat runs for Rust cache hits, release-build duration, test-step compilation, and total elapsed time. Existing sccache archives were cleared before opening this PR; the first run may need to populate the cache.

Change checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas