Add README badges, remove scripts/.gitkeep, and verify shared JSON loader

[GsCommand]

Motivation

• Make the repo visually consistent with Protocol-Commons by adding the same top-of-README badge approach and remove an unnecessary placeholder file in scripts/.
• Ensure the validation toolchain is consolidated around the canonical JSON loader to avoid duplicated duplicate-key/trailing-content checks.
• Keep the change minimal and truthful to the repository state without altering package metadata, versions, or schema semantics.

Description

• Added a top-of-README badge block placed directly under the title that mirrors Protocol-Commons' layout and tone by ordering badges as schema status first, CI workflow second, and license third.
• The exact badges added are: Schemas — v1.1.0 current (shields.io badge linking to the repo), CI Status (GitHub Actions badge pointing at .github/workflows/validate.yml), and License: Apache-2.0 (linking to LICENSE), and no badges were invented for non-existent services.
• Verified that both scripts/validate-all.mjs and scripts/validate-examples.mjs already import and use the shared loadJsonStrict from scripts/load-json-strict.mjs, centralizing duplicate-key and trailing-content checks there, so no behavioral changes to validation were required.
• Removed scripts/.gitkeep because the scripts/ directory contains real tracked files; no placeholder replacement was added and no other files were modified (package.json author and versions left unchanged).

Testing

• Ran npm run validate:schemas, which completed successfully and printed the schema/defs validation success message.
• Ran npm run validate:examples, which completed successfully and validated all example groups per verb.
• Confirmed CHANGELOG.md remains present and intact and still contains entries for both v1.1.0 and v1.0.0.

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Codex Task