Add global synonym set operations

[akshitkrnagpal]

Summary

• add first-class synonym_sets.* and synonym_sets.items.* operations for Typesense v30 global synonym sets
• make collection synonyms.list 404s inspect collection synonym_sets and return actionable guidance
• add CLI examples, README coverage, and patch changeset for CLI/MCP bundles

Verification

• pnpm check
• node packages/cli/dist/cli.js synonym_sets.list --examples
• node packages/cli/dist/cli.js synonym_sets.create --schema

Closes #16