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

README.md

@@ -24,6 +24,46 @@ First run bootstraps a local `.mainline_venv/` and installs deps (`feedparser`,
 
 ---
 
+## Daemon Mode (Recommended for Long-Running)
+
+For persistent displays (e.g., always-on terminal), use daemon mode with command-and-control over ntfy:
+
+```bash
+# Start the daemon (runs in background, auto-warms ntfy topics)
+mise run daemon
+
+# Send commands via cmdline
+mise run cmd "/effects list"
+mise run cmd "/effects noise off"
+mise run cmd "/effects noise intensity 0.5"
+
+# Watch performance stats continuously
+mise run cmd-stats
+
+# Stop the daemon
+mise run daemon-stop
+```
+
+### How It Works
+
+- **Topics**: Uses separate ntfy topics for serial-like communication:
+  - `klubhaus_terminal_mainline_cc_cmd` - commands TO mainline
+  - `klubhaus_terminal_mainline_cc_resp` - responses FROM mainline
+- Topics are automatically created on first daemon start
+
+### Available Commands
+
+```
+/effects list                    - List all effects and status
+/effects <name> on             - Enable an effect
+/effects <name> off            - Disable an effect
+/effects <name> intensity 0.5  - Set effect intensity (0.0-1.0)
+/effects reorder noise,fade,glitch,firehose - Reorder pipeline
+/effects stats                  - Show performance statistics
+```
+
+---
+
 ## Config
 
 All constants live in `engine/config.py`:
@@ -85,9 +125,17 @@ engine/
   sources.py        FEEDS, POETRY_SOURCES, language/script maps
   terminal.py       ANSI codes, tw/th, type_out, boot_ln
   filter.py         HTML stripping, content filter
-  translate.py       Google Translate wrapper + region detection
+  translate.py      Google Translate wrapper + region detection
   render.py         OTF → half-block pipeline (SSAA, gradient)
-  effects.py        noise, glitch_bar, fade, firehose
+  effects/          plugin-based effects system
+    types.py        EffectConfig, EffectContext, EffectPlugin protocol
+    registry.py     Plugin discovery and management
+    chain.py        Ordered pipeline execution
+    performance.py  Performance monitoring
+    controller.py   NTFY command handler
+    legacy.py       Original effects (noise, glitch, fade, firehose)
+  effects_plugins/  External effect plugins (noise, glitch, fade, firehose)
+  display.py        Swappable display backends (TerminalDisplay, NullDisplay)
   fetch.py          RSS/Gutenberg fetching + cache load/save
   ntfy.py           NtfyPoller — standalone, zero internal deps
   mic.py            MicMonitor — standalone, graceful fallback
@@ -96,7 +144,7 @@ engine/
   frame.py          scroll step calculation, timing
   layers.py         ticker zone, firehose, message overlay rendering
   eventbus.py       thread-safe event publishing for decoupled communication
-  events.py         event types and definitions
+  events.py          event types and definitions
   controller.py     coordinates ntfy/mic monitoring and event publishing
   emitters.py       background emitters for ntfy and mic
   types.py          type definitions and dataclasses