Prepare Stack CLI 0.5.1 for registry-only Cargo installation

[konojunya]

Summary

• Name the source package stack-diagram-cli while preserving the stack binary and stack_cli library identity.
• Pin compiler 0.1.0, theme 0.5.0, engine 0.7.0, and formatter 0.1.0 to published registry dependencies; retain the rest of the lockfile.
• Add guarded initial publication and isolated Cargo install verification on four native targets with Rust 1.85.0 and stable.
• Introduce distribution schema v3 for the Cargo identity without modifying historical schemas or activating unpublished channels.
• Package all runtime templates/catalogs and Apache-2.0 notices; remove stale self-update examples.

Validation

• 91 Rust tests including canonical formatter and template conformance
• Rust 1.85.0 and stable tests, Clippy, rustdoc, formatting, release SVG smoke
• Coverage: 92.01% lines, 96.58% functions, 92.12% regions
• 64 JavaScript checks, 12 Python tests, actionlint
• Rust 1.85.0 cargo publish dry-run: 43 files, registry-only dependencies

Release sequence

Existing 0.5.0 archives remain immutable. After main CI, run native release verification and the one-time Cargo publication. Activate installation guidance only after published packages and channel-specific smoke tests pass.