journal_tail: return typed Vec<JournalEntry>, remove Store::load from agent

- journal_tail returns Vec<JournalEntry> with key, content, created_at
- load_startup_journal uses typed API, no more direct Store access
- CLI does formatting, hippocampus returns data

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

src/agent/mod.rs

@@ -497,42 +497,33 @@ impl Agent {
     }
 
     async fn load_startup_journal(&self) {
+        use crate::agent::tools::memory::journal_tail;
+
         let oldest_msg_ts = {
             let ctx = self.context.lock().await;
             ctx.conversation_log.as_ref().and_then(|log| log.oldest_timestamp())
         };
 
-        let store = match crate::store::Store::load() {
-            Ok(s) => s,
+        // Get recent journal entries (newest first)
+        let journal_entries = match journal_tail(None, Some(100), Some(0), None).await {
+            Ok(e) => e,
             Err(_) => return,
         };
 
-        let mut journal_nodes: Vec<_> = store.nodes.values()
-            .filter(|n| n.node_type == crate::store::NodeType::EpisodicSession)
+        // Filter to entries before the conversation started
+        let cutoff_ts = oldest_msg_ts.map(|t| t.timestamp());
+        let filtered: Vec<_> = journal_entries.into_iter()
+            .filter(|e| cutoff_ts.map(|ts| e.created_at < ts).unwrap_or(true))
             .collect();
-        journal_nodes.sort_by_key(|n| n.created_at);
-
-        let cutoff_idx = if let Some(cutoff) = oldest_msg_ts {
-            let cutoff_ts = cutoff.timestamp();
-            let mut idx = journal_nodes.len();
-            for (i, node) in journal_nodes.iter().enumerate() {
-                if node.created_at >= cutoff_ts {
-                    idx = i + 1;
-                    break;
-                }
-            }
-            idx
-        } else {
-            journal_nodes.len()
-        };
 
         let journal_budget = context::context_window() * 15 / 100;
         let mut entries = Vec::new();
         let mut total_tokens = 0;
 
-        for node in journal_nodes[..cutoff_idx].iter().rev() {
-            let ts = chrono::DateTime::from_timestamp(node.created_at, 0);
-            let ast = AstNode::memory(&node.key, &node.content)
+        // Take entries within budget (they're newest-first, so reverse for display)
+        for entry in filtered.iter() {
+            let ts = chrono::DateTime::from_timestamp(entry.created_at, 0);
+            let ast = AstNode::memory(&entry.key, &entry.content)
                 .with_timestamp(ts.unwrap_or_else(chrono::Utc::now));
             let tok = ast.tokens();
             if total_tokens + tok > journal_budget && !entries.is_empty() {