chore(display): add debug logging to NullDisplay for development

- Print first few frames periodically to aid debugging
- Remove obsolete design doc

This helps inspect buffer contents when running headless tests.

docs/superpowers/specs/2026-03-15-readme-update-design.md

@@ -1,145 +0,0 @@
-# README Update Design — 2026-03-15
-
-## Goal
-
-Restructure and expand `README.md` to:
-1. Align with the current codebase (Python 3.10+, uv/mise/pytest/ruff toolchain, 6 new fonts)
-2. Add extensibility-focused content (`Extending` section)
-3. Add developer workflow coverage (`Development` section)
-4. Improve navigability via top-level grouping (Approach C)
-
----
-
-## Proposed Structure
-
-```
-# MAINLINE
-> tagline + description
-
-## Using
-  ### Run
-  ### Config
-  ### Feeds
-  ### Fonts
-  ### ntfy.sh
-
-## Internals
-  ### How it works
-  ### Architecture
-
-## Extending
-  ### NtfyPoller
-  ### MicMonitor
-  ### Render pipeline
-
-## Development
-  ### Setup
-  ### Tasks
-  ### Testing
-  ### Linting
-
-## Roadmap
-
----
-*footer*
-```
-
----
-
-## Section-by-section design
-
-### Using
-
-All existing content preserved verbatim. Two changes:
-- **Run**: add `uv run mainline.py` as an alternative invocation; expand bootstrap note to mention `uv sync` / `uv sync --all-extras`
-- **ntfy.sh**: remove `NtfyPoller` reuse code example (moves to Extending); keep push instructions and topic config
-
-Subsections moved into Using (currently standalone):
-- `Feeds` — it's configuration, not a concept
-- `ntfy.sh` (usage half)
-
-### Internals
-
-All existing content preserved verbatim. One change:
-- **Architecture**: append `tests/` directory listing to the module tree
-
-### Extending
-
-Entirely new section. Three subsections:
-
-**NtfyPoller**
-- Minimal working import + usage example
-- Note: stdlib only dependencies
-
-```python
-from engine.ntfy import NtfyPoller
-
-poller = NtfyPoller("https://ntfy.sh/my_topic/json?since=20s&poll=1")
-poller.start()
-
-# in your render loop:
-msg = poller.get_active_message()  # → (title, body, timestamp) or None
-if msg:
-    title, body, ts = msg
-    render_my_message(title, body)  # visualizer-specific
-```
-
-**MicMonitor**
-- Minimal working import + usage example
-- Note: sounddevice/numpy optional, degrades gracefully
-
-```python
-from engine.mic import MicMonitor
-
-mic = MicMonitor(threshold_db=50)
-if mic.start():                # returns False if sounddevice unavailable
-    excess = mic.excess        # dB above threshold, clamped to 0
-    db = mic.db                # raw RMS dB level
-```
-
-**Render pipeline**
-- Brief prose about `engine.render` as importable pipeline
-- Minimal sketch of serve.py / ESP32 usage pattern
-- Reference to `Mainline Renderer + ntfy Message Queue for ESP32.md`
-
-### Development
-
-Entirely new section. Four subsections:
-
-**Setup**
-- Hard requirements: Python 3.10+, uv
-- `uv sync` / `uv sync --all-extras` / `uv sync --group dev`
-
-**Tasks** (via mise)
-- `mise run test`, `test-cov`, `lint`, `lint-fix`, `format`, `run`, `run-poetry`, `run-firehose`
-
-**Testing**
-- Tests in `tests/` covering config, filter, mic, ntfy, sources, terminal
-- `uv run pytest` and `uv run pytest --cov=engine --cov-report=term-missing`
-
-**Linting**
-- `uv run ruff check` and `uv run ruff format`
-- Note: pre-commit hooks run lint via `hk`
-
-### Roadmap
-
-Existing `## Ideas / Future` content preserved verbatim. Only change: rename heading to `## Roadmap`.
-
-### Footer
-
-Update `Python 3.9+` → `Python 3.10+`.
-
----
-
-## Files changed
-
-- `README.md` — restructured and expanded as above
-- No other files
-
----
-
-## What is not changing
-
-- All existing prose, examples, and config table values — preserved verbatim where retained
-- The Ideas/Future content — kept intact under the new Roadmap heading
-- The cyberpunk voice and terse style of the existing README

engine/display/backends/null.py

@@ -33,6 +33,8 @@ class NullDisplay:
         self._last_buffer = None
 
     def show(self, buffer: list[str], border: bool = False) -> None:
+        import sys
+
         from engine.display import get_monitor, render_border
 
         # Get FPS for border (if available)
@@ -52,6 +54,26 @@ class NullDisplay:
             buffer = render_border(buffer, self.width, self.height, fps, frame_time)
 
         self._last_buffer = buffer
+
+        # For debugging: print first few frames to stdout
+        if hasattr(self, "_frame_count"):
+            self._frame_count += 1
+        else:
+            self._frame_count = 0
+
+        # Only print first 5 frames or every 10th frame
+        if self._frame_count <= 5 or self._frame_count % 10 == 0:
+            sys.stdout.write("\n" + "=" * 80 + "\n")
+            sys.stdout.write(
+                f"Frame {self._frame_count} (buffer height: {len(buffer)})\n"
+            )
+            sys.stdout.write("=" * 80 + "\n")
+            for i, line in enumerate(buffer[:30]):  # Show first 30 lines
+                sys.stdout.write(f"{i:2}: {line}\n")
+            if len(buffer) > 30:
+                sys.stdout.write(f"... ({len(buffer) - 30} more lines)\n")
+            sys.stdout.flush()
+
         if monitor:
             t0 = time.perf_counter()
             chars_in = sum(len(line) for line in buffer)