Refactor event payload handling across adapters

- Introduced `event-payload` crate to centralize event payload definitions.
- Updated NATS and PostgreSQL adapters to use the new `EventPayload` type.
- Removed redundant event payload definitions and conversion implementations from NATS and PostgreSQL adapters.
- Simplified SQLite event queue to utilize the new `EventPayload`.
- Refactored wiring functions for PostgreSQL and SQLite to improve database connection handling and migration.
- Cleaned up presentation and worker crates by removing unused event publisher dependencies and related wiring functions.

crates/adapters/postgres-event-queue/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 sqlx        = { version = "0.8.6", features = ["runtime-tokio-rustls", "postgres", "macros", "chrono"] }
 domain      = { workspace = true }
+event-payload = { workspace = true }
 anyhow      = { workspace = true }
 async-trait = { workspace = true }
 serde       = { workspace = true }