Mismatch on dialyzer types for create_key

[jaeyson]

Fixes #95

Summary by Sourcery

Align type specifications and payload handling with actual usage, and update documentation and tooling for local Typesense development.

Bug Fixes:

• Correct dialyzer typespecs for API functions such as create_key and other resource operations to match accepted payload types, including maps and structs.
• Ensure Ecto-like structs have internal metadata fields (e.g. metadata) stripped before being sent as document bodies.

Enhancements:

• Broaden typespecs across collections, analytics, synonyms, curations, conversation models, stopwords, presets, and natural language APIs to accept both raw maps and generated OpenApi schema structs.
• Normalize keyword argument typespecs and parameter annotations for various retrieve, upsert, and delete functions for better static analysis and IDE support.

Build:

• Bump the library version to 2.3.1 and record changes in the changelog.

Deployment:

• Update the default docker-compose Typesense image version to 30.1 for local development.

Documentation:

• Add example docker-compose configuration for running a local Typesense instance to the README and local running guide.
• Document the expanded payload flexibility in typespecs implicitly via updated examples and references.