Clarify release authority for v1.1.0 and mark v1.0.0 as archival

[GsCommand]

Motivation

• Tighten the repository release story so reviewers read one coherent current-line authority instead of mixed draft signals.
• Remove ambiguous wording that could be read as claiming external publication or mirror proof that the repo does not provide yet.
• Make preserved legacy surfaces explicitly archival so they cannot be mistaken for current authoritative artifacts.

Description

• Rewrite README.md to present a single current-line authority: explicit v1.1.0 root surfaces (agents/v1.1.0/, schemas/v1.1.0/, meta/, .well-known/, checksums.txt), clarify dist-pin/ as a derivative bundle, and mark .well-known/ as discovery-only.
• Complete and normalize the Commons and Commercial source/mirror pattern examples so the mirror URLs are documented and the binding patterns are unambiguous.
• Update SPEC.md to remove wording drift around the “current schema files” transition, explicitly list the repo-owned v1.1.0 schema files, and separate legacy v1.0.0 schema material as archival-only while preserving the protocol meaning.
• Harden archival framing in the preserved v1.0.0 dist-pin metadata by changing descriptions to “archival-only”, repointing legacy registry HTTP links at the archived v1.0.0 manifest path, and adding superseded_by and authority_scope notices; regenerate checksums.txt to reflect those metadata updates.

Testing

• Ran node scripts/generate-checksums.mjs to regenerate integrity digests, which completed successfully.
• Ran npm run validate, which verifies local structure, manifest/card alignment, and checksums, and completed successfully.
• Ran npm run validate:release; local manifest and derivative-bundle reproducibility checks passed, but external resolution of upstream tagged schema URLs failed in this environment (expected when mirrors/upstream are not reachable), so full publish-scoped URL resolution remains to be verified in a networked publish step.

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Codex Task