Spacebar toggle for all agents, persist to config, scan agent directory

- Scan agents directory for all .agent files instead of hardcoded list
- Persist enabled state to ~/.consciousness/agent-enabled.json
- Spacebar on F3 agent list toggles selected agent on/off
- Both subconscious and unconscious agents support toggle
- Disabled agents shown dimmed with "off" indicator
- New agents default to disabled (safe default)

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

src/user/mod.rs

@@ -109,6 +109,8 @@ struct App {
     agent_state: Vec<crate::mind::SubconsciousSnapshot>,
     unconscious_state: Vec<crate::mind::UnconsciousSnapshot>,
     graph_health: Option<crate::subconscious::daemon::GraphHealth>,
+    /// Agent toggle requests from UI — consumed by mind loop.
+    pub agent_toggles: Vec<String>,
     walked_count: usize,
     channel_status: Vec<ChannelStatus>,
     idle_info: Option<IdleInfo>,
@@ -134,6 +136,7 @@ impl App {
             agent_state: Vec::new(),
             unconscious_state: Vec::new(),
             graph_health: None,
+            agent_toggles: Vec::new(),
             walked_count: 0,
             channel_status: Vec::new(), idle_info: None,
         }
@@ -374,6 +377,18 @@ async fn run(
         idle_state.decay_ewma();
         app.update_idle(&idle_state);
         app.agent_state = mind.subconscious_snapshots().await;
+        {
+            let toggles: Vec<String> = app.agent_toggles.drain(..).collect();
+            if !toggles.is_empty() {
+                let mut sub = mind.subconscious.lock().await;
+                let mut unc = mind.unconscious.lock().await;
+                for name in &toggles {
+                    if sub.toggle(name).is_none() {
+                        unc.toggle(name);
+                    }
+                }
+            }
+        }
         {
             let unc = mind.unconscious.lock().await;
             app.unconscious_state = unc.snapshots();