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/cli/journal.rs

@@ -68,10 +68,17 @@ pub fn cmd_tail(n: usize, full: bool, provenance: Option<&str>, dedup: bool) ->
 }
 
 pub async fn cmd_journal_tail(n: usize, full: bool, level: u8) -> Result<(), String> {
-    let format = if full { Some("full") } else { Some("compact") };
-    let result = memory::journal_tail(None, Some(n as u64), Some(level as u64), format, None).await
+    let entries = memory::journal_tail(None, Some(n as u64), Some(level as u64), None).await
         .map_err(|e| e.to_string())?;
-    print!("{}", result);
+    for entry in entries {
+        if full {
+            println!("--- {} ---", entry.key);
+            println!("{}\n", entry.content);
+        } else {
+            let first_line = entry.content.lines().next().unwrap_or("(empty)");
+            println!("{}: {}", entry.key, first_line);
+        }
+    }
     Ok(())
 }