Respect $ref sibling semantics for default/examples by draft

Summary

This PR makes the ValidDefault and ValidExamples linter rules draft-aware when the keyword appears as a sibling of $ref.

What changed

• In Draft 7 and older, if a schema object contains both $ref and:

  • default (for ValidDefault), or
  • examples (for ValidExamples)

  the rule now skips linting/transforming that object (because siblings of $ref must be ignored in those drafts).

• In 2019-09 and 2020-12, the rules continue to lint those siblings and will still remove invalid default / examples values.

Tests added

For both valid_default and valid_examples, new tests cover:

• Draft-07: sibling is preserved (ignored)
• 2019-09: invalid sibling is removed
• 2020-12: invalid sibling is removed

Local verification

• Ran make configure compile
• Ran make (including tests); passed

Review & Testing Checklist for Human

• Confirm the dialect detection via vocabularies (meta-data vocab presence) is the right signal for distinguishing 2019-09+/2020-12 from Draft-07/06/04 in all linter execution paths.
• Review the new guard in both ValidDefault::condition and ValidExamples::condition to ensure the scope is correct (only $ref sibling cases, no unintended skips).
• Run/inspect blaze.linter tests (or full make) and verify the new draft-specific cases match expected JSON Schema semantics end-to-end.

Notes

• This change addresses the reported issue around $ref sibling handling in older drafts for shipped lint rules.
• Link to Devin Session: https://staging.itsdev.in/sessions/c3a4f1853d624f9cbbb6dd47a040a902
• Requested by: bot_apk