Remove dead code: append_text, needs_assistant_marker, target param

append_text was the TextDelta streaming handler — replaced by
append_streaming on Agent entries. needs_assistant_marker tracked
turn boundaries for the old message path. target removed from
Agent::turn — routing now determined by entry content.

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

src/agent/mod.rs

@@ -178,7 +178,7 @@ pub struct Agent {
     /// TODO: move to Session — it's session-level, not agent-level.
     pub agent_cycles: crate::subconscious::subconscious::AgentCycleState,
     /// Shared active tools — Agent writes, TUI reads.
-    pub active_tools: crate::agent::tools::SharedActiveTools,
+    pub active_tools: tools::SharedActiveTools,
 }
 
 fn render_journal(entries: &[context::JournalEntry]) -> String {
@@ -326,7 +326,6 @@ impl Agent {
     pub async fn turn(
         agent: Arc<tokio::sync::Mutex<Agent>>,
         user_input: &str,
-        target: StreamTarget,
     ) -> Result<TurnResult> {
         // --- Pre-loop setup (lock 1): agent cycle, memories, user input ---
         let active_tools = {
@@ -567,7 +566,7 @@ impl Agent {
     /// Used by `turn()` which manages its own locking.
     async fn dispatch_tool_call_unlocked(
         agent: &Arc<tokio::sync::Mutex<Agent>>,
-        active_tools: &crate::agent::tools::SharedActiveTools,
+        active_tools: &tools::SharedActiveTools,
         call: &ToolCall,
         ds: &mut DispatchState,
     ) {