feat: add scoped multimodal image attachments

crates/llm-engine/Cargo.toml

@@ -7,7 +7,7 @@ license.workspace = true
 
 [features]
 default = []
-codex = ["dep:base64", "dep:chrono"]
+codex = ["dep:chrono"]
 
 [dependencies]
 serde = { workspace = true, features = ["derive"] }
@@ -21,7 +21,7 @@ tokio-util = "0.7"
 reqwest = { version = "0.13", default-features = false, features = ["stream", "json", "native-tls", "http2"] }
 eventsource-stream = "0.2"
 zstd = "0.13"
-base64 = { version = "0.22.1", optional = true }
+base64 = "0.22.1"
 chrono = { version = "0.4", default-features = false, features = ["serde", "clock"], optional = true }
 llm-engine-macros = { workspace = true }