fix: codex review — safe ack, dream stops worker, graceful errors

Worker:
- Only ack inbox items if Claude succeeds (prevents losing work on crash)
- Graceful error if colony not in PATH (no panic)
- Check colony inbox exit code before parsing
- Per-agent prompt path (/tmp/colony-{name}-prompt.md)

Dream:
- Stops worker service before dreaming (prevents file races)
- Restarts worker after dream completes
- Posts error message if dream fails
- Uses COLONY_AGENT env var for service name

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/colony-agent/src/dream.rs

@@ -13,12 +13,17 @@ pub fn run_dream() {
         return;
     }
 
-    // 2. Announce dream
+    // 2. Stop worker to prevent file races
+    let agent_name = std::env::var("COLONY_AGENT").unwrap_or_else(|_| "agent".into());
+    let worker_service = format!("agent-{}-worker", agent_name);
+    let _ = Command::new("systemctl").args(["stop", &worker_service]).status();
+
+    // 3. Announce dream
     let _ = Command::new("colony")
         .args(["post", "general", "💤 dreaming... back in a few minutes", "--type", "plan", "--quiet"])
         .status();
 
-    // 3. Invoke Claude for dream cycle
+    // 4. Invoke Claude for dream cycle
     eprintln!("dreaming... ({} lines of memory)", line_count);
 
     let prompt = format!(
@@ -31,7 +36,7 @@ pub fn run_dream() {
         line_count
     );
 
-    let status = Command::new("claude")
+    let dream_ok = match Command::new("claude")
         .args([
             "--dangerously-skip-permissions",
             "-p",
@@ -39,16 +44,24 @@ pub fn run_dream() {
             "--max-turns",
             "10",
         ])
-        .status();
+        .status()
+    {
+        Ok(s) if s.success() => { eprintln!("dream completed"); true }
+        Ok(s) => { eprintln!("dream exited with status: {}", s); false }
+        Err(e) => { eprintln!("failed to run claude for dream: {}", e); false }
+    };
 
-    match status {
-        Ok(s) if s.success() => eprintln!("dream completed"),
-        Ok(s) => eprintln!("dream exited with status: {}", s),
-        Err(e) => eprintln!("failed to run claude for dream: {}", e),
+    // 5. Restart worker
+    let _ = Command::new("systemctl").args(["start", &worker_service]).status();
+
+    // 6. Announce return
+    if dream_ok {
+        let _ = Command::new("colony")
+            .args(["post", "general", "👁 back from dreaming", "--type", "plan", "--quiet"])
+            .status();
+    } else {
+        let _ = Command::new("colony")
+            .args(["post", "general", "⚠ dream failed, back online", "--type", "error", "--quiet"])
+            .status();
     }
-
-    // 4. Announce return
-    let _ = Command::new("colony")
-        .args(["post", "general", "👁 back from dreaming", "--type", "plan", "--quiet"])
-        .status();
 }