feat(daemon): add daemon mode with C&C and display abstraction

- Add display abstraction with swappable backends (TerminalDisplay, NullDisplay)
- Separate C&C into RX/TX topics for serial-like communication
- Add StreamController with automatic ntfy topic warmup
- Add performance monitoring for render + display stages
- Update AGENTS.md and README.md with daemon/cmd operating procedures
- Add clean/clobber tasks to mise.toml
- Add tests for display, effects controller, and controller warmup
- Fix bug where /effects reorder command was unreachable

engine/scroll.py

@@ -4,10 +4,16 @@ Orchestrates viewport, frame timing, and layers.
 """
 
 import random
-import sys
 import time
 
 from engine import config
+from engine.display import (
+    Display,
+    TerminalDisplay,
+)
+from engine.display import (
+    get_monitor as _get_display_monitor,
+)
 from engine.frame import calculate_scroll_step
 from engine.layers import (
     apply_glitch,
@@ -16,24 +22,24 @@ from engine.layers import (
     render_message_overlay,
     render_ticker_zone,
 )
-from engine.terminal import CLR
 from engine.viewport import th, tw
 
 USE_EFFECT_CHAIN = True
 
 
-def stream(items, ntfy_poller, mic_monitor):
+def stream(items, ntfy_poller, mic_monitor, display: Display | None = None):
     """Main render loop with four layers: message, ticker, scroll motion, firehose."""
+    if display is None:
+        display = TerminalDisplay()
     random.shuffle(items)
     pool = list(items)
     seen = set()
     queued = 0
 
     time.sleep(0.5)
-    sys.stdout.write(CLR)
-    sys.stdout.flush()
-
     w, h = tw(), th()
+    display.init(w, h)
+    display.clear()
     fh = config.FIREHOSE_H if config.FIREHOSE else 0
     ticker_view_h = h - fh
     GAP = 3
@@ -97,6 +103,7 @@ def stream(items, ntfy_poller, mic_monitor):
         buf.extend(ticker_buf)
 
         mic_excess = mic_monitor.excess
+        render_start = time.perf_counter()
 
         if USE_EFFECT_CHAIN:
             buf = process_effects(
@@ -119,12 +126,16 @@ def stream(items, ntfy_poller, mic_monitor):
         if msg_overlay:
             buf.extend(msg_overlay)
 
-        sys.stdout.buffer.write("".join(buf).encode())
-        sys.stdout.flush()
+        render_elapsed = (time.perf_counter() - render_start) * 1000
+        monitor = _get_display_monitor()
+        if monitor:
+            chars = sum(len(line) for line in buf)
+            monitor.record_effect("render", render_elapsed, chars, chars)
+
+        display.show(buf)
 
         elapsed = time.monotonic() - t0
         time.sleep(max(0, config.FRAME_DT - elapsed))
         frame_number += 1
 
-    sys.stdout.write(CLR)
-    sys.stdout.flush()
+    display.cleanup()