Fix Tonic conversion tests and release 0.20.7

[RAprogramm]

Summary

• switch the tonic conversion tests to the infallible Status::from API so clippy stops flagging unnecessary fallible conversions
• rewrite the AppResult alias regression test to assert through pattern matching instead of literal unwrap
• bump the crate metadata to 0.20.7 and update the changelog/README accordingly

Testing

• cargo +nightly fmt --
• cargo +1.90.0 clippy --all-features --all-targets -- -D warnings
• cargo +1.90.0 build --all-targets
• cargo +1.90.0 test --all
• cargo +1.90.0 doc --no-deps
• cargo audit
• cargo deny check

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https://chatgpt.com/codex/tasks/task_e_68d39d164ba8832ba3ec5ec711cad59e