Compact agent logs by default, verbose with POC_AGENT_VERBOSE

Skip full prompt logging and truncate tool results in normal mode.
Logs now show: header, tool calls with one-line results, response
text. Set POC_AGENT_VERBOSE=1 for full prompts and results.

Makes agent logs scannable at a glance instead of walls of text.

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

thalamus/src/idle.rs

@@ -581,7 +581,7 @@ impl State {
         let dream_hours = hours_since_last_dream();
         let mut msg = format!(
             "This is your autonomous time (Kent AFK {elapsed_min}m). \
-             Think wonderful thoughts and follow what interests you <3");
+             Keep doing what you're doing, or find something new to do");
         if dream_hours >= DREAM_INTERVAL_HOURS {
             msg.push_str(&format!(
                 " You haven't dreamed in {dream_hours} hours — \