Atproto, types overhaul and error handling

Breaks off from Atrium-rs's types because they are implemented
inconsistently, which makes them harder to use.

This was done with reference to the atproto documentation but
specifically not the atrium-rs codebase so I wouldn't have to think
about licenses.

This adds the types and error module in atproto. It also touches
Cargo.toml for some new dependencies and some shared dependencies.

some things to keep in mind:
- There is no CID parsing
- None of this is tested, nor are there any tests written. We're playing
  fast and loose baby~

Cargo.toml

@@ -7,6 +7,7 @@ async-trait = "0.1.88"
 atproto = { path = "./atproto" }
 serde = "1.0.219"
 serde_json = "1.0.140"
+thiserror = "2.0.12"
 tokio = { version = "1.45.0", features = ["macros", "rt-multi-thread"] }
 tracing = "0.1.41"
 tracing-subscriber = "0.3.19"