#64 Add explicit metadata for synthetic-only fixture assumptions FIXED

[Kappa16]

Summary

Adds a required per-destination fixture_status field to distinguish synthetic-only fixtures from future network-visible fixtures. All existing destinations are marked as synthetic-only, and validation now rejects missing or unknown status values. This prevents consumers from interpreting synthetic fixture labels as live Horizon truth.

Type of change

• Fixture change — adds, removes, or rescores a destination or asset
• Transaction change — adds or removes a sample XDR
• Documentation only — README, CONTRIBUTING, CHANGELOG prose, etc.
• CI / tooling

Changelog

• I have added an entry under [Unreleased] in CHANGELOG.md describing what changed and why.

Briefly summarise the changelog entry here:

Added the required per-fixture fixture_status field and marked all existing destinations as synthetic-only. No destination scores were changed.

Score-regression guard

• The score changes in this PR are intentional and are documented in CHANGELOG.md.
• N/A — no scores were changed.

Validation

• npm run validate passes locally.

Additional test result:

npm test
49 tests passed
0 failed

Validation result:

Fixture validation passed: 12 destinations, 12 scores.
Scenario validation passed: 1 scenario(s).

Related issues

Resolves the per-destination fixture lifecycle status issue described in this PR.

Horizon lookups were not added, in accordance with the issue scope.
CLOSE #64

[Kappa16]

@knytcomics-ui PLS maintainer when you are done reviewing ,pls when you get the chance pls issue payment via grantfox as this will encourage me to keep on contributing ....thank you