Add enabled toggle to AutoAgent, simplify unconscious scheduling

- AutoAgent.enabled: universal toggle for any auto agent
- Subconscious: should_trigger checks auto.enabled
- Unconscious: simplified from consolidation-plan-driven budgets to
  simple loop with cooldown. Static agent list, max 2 concurrent.
- TUI: unconscious agents shown in F3 subconscious screen under
  separator, with enabled/running/runs display

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

src/mind/subconscious.rs

@@ -291,6 +291,7 @@ const AGENTS: &[(&str, u64)] = &[
 pub struct SubconsciousSnapshot {
     pub name: String,
     pub running: bool,
+    pub enabled: bool,
     pub current_phase: String,
     pub turn: usize,
     pub last_run_secs_ago: Option<f64>,
@@ -352,7 +353,7 @@ impl SubconsciousAgent {
     }
 
     fn should_trigger(&self, conversation_bytes: u64, interval: u64) -> bool {
-        if self.is_running() { return false; }
+        if !self.auto.enabled || self.is_running() { return false; }
         if interval == 0 { return true; }
         conversation_bytes.saturating_sub(self.last_trigger_bytes) >= interval
     }
@@ -361,6 +362,7 @@ impl SubconsciousAgent {
         SubconsciousSnapshot {
             name: self.name.clone(),
             running: self.is_running(),
+            enabled: self.auto.enabled,
             current_phase: self.auto.current_phase.clone(),
             turn: self.auto.turn,
             last_run_secs_ago: self.last_run.map(|t| t.elapsed().as_secs_f64()),