Icod.Tar 1.0.2: release preparation and documentation

[uniblab]

Prepare Icod.Tar 1.0.2 following the build/CI normalization merged in PR #4.

Version alignment

• bump Version and PackageVersion to 1.0.2;
• bump AssemblyVersion to 1.0.2.0;
• update tar --version to report 1.0.2;
• refresh NuGet PackageReleaseNotes for the maintenance release.

README

• add the canonical pull-request Staging badge;
• add the canonical main Release-validation badge;
• document the purpose of the 1.0.2 maintenance release;
• update the NuGet installation example to 1.0.2;
• document runtime/dependency information;
• document local Debug build stages and the complete CI/release lifecycle;
• document that the root README.md is also the NuGet package README and is included in release archives;
• document the repository version/release contract.

Documentation audit

The repository contains two Markdown documents: root README.md and packaging/README.md. Both were audited and refreshed for completeness.

packaging/README.md now documents:

• the validation ladder;
• repository/package identity and package-readme behavior;
• each packaging/build helper;
• the Tar-specific distribution smoke retained after normalization;
• the tagged-release dependency graph;
• six RID archive outputs;
• NuGet Trusted Publishing prerequisites including the Release environment;
• version/tag/package-selection rules; and
• retry behavior through --skip-duplicate.

No Tar command behavior change is intended relative to 1.0.1; this is a maintenance/repository-release release.