0.1.3: Add typed Event subclasses and Psr3LoggerProvider

Replace the generic Event class (final, untyped payload) with an
abstract Event base and three typed subclasses: ErrorEvent, LogEvent,
and TransactionEvent.  Providers now receive typed accessors
(getException(), getMessage(), getLevel(), getContext(), etc.) through
instanceof checks, while getType()/getPayload() remain available for
transport-oriented providers like DuckBugProvider.

Client constructs the typed subclasses directly, passing original data
(Throwable, level, message, Transaction) alongside the wire payload.
No changes to payload building, dispatch logic, or DuckBugProvider.

Add Psr3LoggerProvider — a built-in adapter that wraps any
Psr\Log\LoggerInterface as a DuckBug provider for fan-out to existing
logging infrastructure (Monolog, Graylog, file loggers, etc.).

Update README with typed provider examples, Psr3LoggerProvider usage,
and a PSR-3 drop-in section.

Made-with: Cursor

0.1.1

moved sensitive fields to Pond

0.1.0

Quack