fix(everything): clarify resource link ID mapping

[Joosboy]

Summary

• Clarify the get-resource-links resource ID mapping in the Everything server docs.
• Rename the local boolean so the implementation reads as "even IDs are text, odd IDs are blob" instead of using a misleading isOdd name.

Why

Issue #475 notes that odd/even resource wording can be confusing. The current Everything server uses dynamic text/{resourceId} and blob/{resourceId} templates; this keeps the existing behavior and documents the mapping used by get-resource-links.

Validation

• npm test --workspace @modelcontextprotocol/server-everything -- __tests__/tools.test.ts
• npm run build --workspace @modelcontextprotocol/server-everything
• npx prettier --check src/everything/tools/get-resource-links.ts src/everything/docs/features.md

Related issue

Refs #475