Retire Scheduler on ZCode 3.5.2 and newer

[notmike101]

Summary

• release Scheduler 0.1.7 as the retirement metadata update
• cap the plugin compatibility range below ZCode 3.5.2, where native automation and scheduling replaces it
• document the retirement and lock the compatibility range in tests

Verification

• bun run check
• bun run release:package -- --tag v0.1.7
• semver boundary check: 3.5.1 accepted; 3.5.2, 3.6.0, and 4.0.0 rejected