feat(channels/discord) Outbound file/image attachments + image_cache hardening

crates/openfang-api/src/openai_compat.rs

@@ -216,7 +216,11 @@ fn convert_messages(oai_messages: &[OaiMessage]) -> Vec<Message> {
                                             .unwrap_or(parts[0])
                                             .to_string();
                                         let data = parts[1].to_string();
-                                        Some(ContentBlock::Image { media_type, data })
+                                        Some(ContentBlock::Image {
+                                            media_type,
+                                            data,
+                                            source_url: None,
+                                        })
                                     } else {
                                         None
                                     }

crates/openfang-api/src/routes.rs

@@ -280,6 +280,7 @@ pub fn resolve_attachments(
                 blocks.push(openfang_types::message::ContentBlock::Image {
                     media_type: content_type,
                     data: b64,
+                    source_url: None,
                 });
             }
             Err(e) => {
@@ -512,6 +513,7 @@ pub async fn get_agent_session(
                                 openfang_types::message::ContentBlock::Image {
                                     media_type,
                                     data,
+                                    ..
                                 } => {
                                     texts.push("[Image]".to_string());
                                     // Persist image to upload dir so it can be

crates/openfang-channels/Cargo.toml

@@ -29,6 +29,7 @@ sha1 = { workspace = true }
 aes = "0.8"
 cbc = "0.1"
 base64 = { workspace = true }
+bytes = { workspace = true }
 hex = { workspace = true }
 html-escape = { workspace = true }
 regex-lite = "0.1"
@@ -42,3 +43,4 @@ rumqttc = { workspace = true }
 
 [dev-dependencies]
 tokio-test = { workspace = true }
+tempfile = { workspace = true }