fix scoring: HTTP error checking, context refresh, chunk logging

Check HTTP status from logprobs API (was silently ignoring 500s).
Call publish_context_state() after storing scores so F10 screen
updates. Add chunk size logging for OOM debugging.

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

src/agent/runner.rs

@@ -882,7 +882,7 @@ impl Agent {
     }
 
     /// Push the current context summary to the shared state for the TUI to read.
-    fn publish_context_state(&self) {
+    pub fn publish_context_state(&self) {
         let summary = self.context_state_summary();
         if let Ok(mut dbg) = std::fs::OpenOptions::new().create(true).append(true)
                 .open("/tmp/poc-journal-debug.log") {