Release v0.2.0

[Sreehari425]

This pull request releases PresenceForge v0.2.0, introducing major new features, API changes, and documentation updates. The most significant additions are a new IPC event system (allowing event subscription and polling), improvements to IPC discovery, enhancements to the activity builder, and a refactored error model with more granular types. The documentation and examples have been updated to reflect these changes.

New IPC Event System:

• Added event subscription API (subscribe, unsubscribe, next_event, poll_event) for both sync and async clients, with typed event models and new example code. [1] [2] [3] [4] [5] [6]

Error Model Refactor (Breaking):

• Replaced string-based errors with typed error kinds (HandshakeFailureKind, InvalidResponseKind, etc.), updated DiscordIpcError variants, and improved error documentation. [1] [2] [3]

Activity Builder Enhancements:

• Added .end_timestamp_from_now(Duration) and .party_simple() methods for easier activity configuration, with updated documentation and examples. [1] [2] [3] [4] [5]

IPC Discovery Improvements:

• Introduced a new IPC discovery module with broader coverage for Unix environments and shared helpers across runtimes.

Documentation and Versioning Updates:

• Updated all docs, examples, and badges to reference v0.2.0, documented new APIs, and improved usage guidance throughout. [1] [2] [3] [4] [5] [6]

Please refer to the new changelogs/0.2.0.md for a full breakdown of changes.

closes #11

[Sreehari425]

@copilot review my code