SDK sausage-actor; examples and agent on the SDK; agent without limits

- sausage-actor: Message, messages(), send/reply/publish, async Inbox
- agent: append-only /data/history.jsonl, no caps on history, steps, waits,
  tool output, or reads; max_tokens only when configured (Anthropic: 32000)

agent/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2024"
 description = "The Sausage agent actor."
 
 [dependencies]
-async-channel = "2"
+sausage-actor = { version = "0.1", path = "../sdk", features = ["async"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 wstd = "0.6"