Align organization defaults with the NikaS repository contract

[NikaSir]

Problem

Organization defaults still recommend a generic validate context and contain release-tag traceability language. They need to point to the shared repository contract and distinguish tooling validation from verified product behavior.

Changes

• Mirror Repository Contract v1.0 with an exact canonical commit and document hash.
• Verify the local mirror pin/digest in the existing standards workflow.
• Update repository, contribution and PR guidance for actual production artifacts, data quality, commands, lifecycle and evidence.
• Require unique CI job names while preserving existing mandatory checks and main/HACS publication.

Validation and scope

• Existing UI v2.2 mirror validation passes.
• Repository-contract mirror digest and exact canonical source match.
• JSON/YAML syntax and git diff checks pass.
• Independent review found no blocking issues.

This PR updates shared defaults and does not configure consumer branch protection, alter runtime/UI behavior or claim consumer compliance. The canonical package is merged in main.

Canonical package: NikaSir/ha-contract-generated-ui#138
Pinned canonical commit: 78150ef18514ace061ba60fbd509e05f4810ba05 (merged via PR #138).