Revert output tool hacks (AST scanning + silent success)

These were wrong approaches — replacing with proper closure-based
output tool that writes directly to shared Subconscious state.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/oneshot.rs

@@ -165,28 +165,6 @@ impl AutoAgent {
                 .map_err(|e| format!("{}: {}", self.name, e))?;
 
             if result.had_tool_calls {
-                // Extract output() calls from the conversation
-                let ctx = backend.0.context.lock().await;
-                for node in ctx.conversation() {
-                    if let super::context::AstNode::Branch { children, .. } = node {
-                        for child in children {
-                            if let Some(leaf) = child.leaf() {
-                                if let super::context::NodeBody::ToolCall { name, arguments } = leaf.body() {
-                                    if name == "output" {
-                                        if let Ok(args) = serde_json::from_str::<serde_json::Value>(arguments) {
-                                            let key = args["key"].as_str().unwrap_or("");
-                                            let value = args["value"].as_str().unwrap_or("");
-                                            if !key.is_empty() {
-                                                self.outputs.insert(key.to_string(), value.to_string());
-                                            }
-                                        }
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-                drop(ctx);
                 continue;
             }
 

src/agent/tools/memory.rs

@@ -245,13 +245,11 @@ fn output(args: &serde_json::Value) -> Result<String> {
         anyhow::bail!("invalid output key: {}", key);
     }
     let value = get_str(args, "value")?;
-    // Write to disk if output dir is set (subprocess agents),
+    let dir = std::env::var("POC_AGENT_OUTPUT_DIR")
-    // otherwise just return success (forked agents extract from AST)
+        .map_err(|_| anyhow::anyhow!("no output directory set"))?;
-    if let Ok(dir) = std::env::var("POC_AGENT_OUTPUT_DIR") {
+    let path = std::path::Path::new(&dir).join(key);
-        let path = std::path::Path::new(&dir).join(&key);
+    std::fs::write(&path, value)
-        std::fs::write(&path, &value)
         .with_context(|| format!("writing output {}", path.display()))?;
-    }
     Ok(format!("{}: {}", key, value))
 }