release: prepare 0.0.5

[m1ngsama]

Summary

• bump the package and lockfile version from 0.0.4 to 0.0.5
• close the current changelog entries under 0.0.5 - 2026-08-11 while retaining an empty Unreleased section
• include the product documentation and tut(1) installation work in the release record

Release scope

This PR intentionally changes only Cargo.toml, the root tut entry in Cargo.lock, and CHANGELOG.md. The README, manual, CLI, tests, and Makefile derive or avoid the package version and require no release-only edits.

Validation

• current stable: fmt, diff check, strict Clippy, full 369 unit + 28 CLI/real-PTY + 5 documentation tests
• Rust 1.88: strict Clippy and the same full test matrix
• release profile with overflow checks: the same full test matrix
• locked Cargo metadata, package ID, documentation contract, and expected tut-0.0.5.crate derivation

Post-merge release gates

After this PR and its exact main merge SHA pass CI, the release will be built from a clean detached worktree. The crate provenance, local digest, signed annotated tag, GitHub asset digest, public re-download, tests, installation, installcheck, and uninstall will all be verified before completion.