[FEATURE]: enum-value-formatting: harden meta:enum handling and issue paths

[Mehrn0ush]

Describe the feature

Harden tools/src/main/js/linter/checks/enum-value-formatting.check.js so meta:enum handling is deterministic and lint output is accurate/noise-free (especially for edge-case inputs).

Use-cases

• Schemas that correctly use meta:enum should not trigger false positives (e.g., “missing description” when the key exists).
• Schemas with malformed meta:enum (wrong type, inherited properties) should produce a clear error instead of silent/incorrect behavior.
• Reports should point to the correct location (meta:enum paths), and duplicate enum literals should not generate duplicate issues.

Scope / Out of scope

• Scope: this single check file only.
• Out of scope: changing the public API/config of the linter; adding new dependencies.

Possible solutions

Proposed changes (all within the check):

1. Use own-property detection for meta:enum on the parent:

   • Replace 'meta:enum' in parent with Object.prototype.hasOwnProperty.call(parent, 'meta:enum')
     to avoid consulting the prototype chain (hardens the check against prototype-chain manipulation,
     including prototype-pollution scenarios).

2. Validate meta:enum type before using it:

   • Require a plain object (non-null object, not array, prototype is Object.prototype or null).
   • If present but invalid, emit one ERROR:
     • Message: meta:enum must be a plain object mapping enum values to descriptions.
     • Context: actualType (array or typeof).

3. Fix coverage logic:

   • Replace !metaEnum[value] with !Object.prototype.hasOwnProperty.call(metaEnum, value) to test key presence only.
   • Avoid counting inherited keys as “present”.

4. Fix path reporting:

   • Avoid literal "undefined" / "null" paths by using a safe fallback for paths.
   • Derive a single metaEnumBasePath by replacing trailing .enum with .meta:enum (and handle root / fallback cases).
   • Report “missing description” at the meta:enum location, not the enum array.

5. De-duplicate enum-value checks:

   • Iterate over unique string values (Set) so duplicate enum literals don't emit duplicate issues.

Additional context

• File: tools/src/main/js/linter/checks/enum-value-formatting.check.js
• Current implementation: https://github.com/CycloneDX/specification/blob/2.0-dev/tools/src/main/js/linter/checks/enum-value-formatting.check.js