Initial commit — Amirine Cosplay Lights

Arduino Uno + WS2812B LED strip controller with a text-based lightshow
system. Shows are defined as .txt files (hex color + fade duration per step),
converted to PROGMEM headers by convert_all.py, and navigated at runtime
via a debounced button (tap/double-tap/hold). BSD 2-Clause license.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PLAN.md

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+# Project Plan — Amirine Cosplay Lights
+
+This file records the original design brief and decisions so future contributors can understand why things are built the way they are.
+
+---
+
+## Goals
+
+1. **Light show player** — load `.txt` files that define a sequence of colors with transition durations. Steps fade from the previous color to the next over the specified time. Setting duration to `0ms` gives an instant switch; high values (e.g. `5000ms`) give a slow fade.
+
+2. **Multi-show navigation** — all shows are compiled into the firmware. A single button lets you cycle through them:
+   - 1 tap — next show
+   - 2 taps — previous show
+   - Hold — reset to show 0 (slow blue pulse)
+
+3. **Arduino + WS2812B** — runs on an Arduino Uno with a WS2812B (NeoPixel) LED strip.
+
+4. **Open source** — BSD 2-Clause license. Free for any use, personal or commercial.
+
+5. **Designed for expansion** — the LED controller layer (`led_controller.h/.cpp`) is structured so that new patterns (chase, sparkle, gradient) can be added later without touching show playback logic.
+
+---
+
+## Hardware confirmed
+
+- **Board:** Arduino Uno
+- **LED strip:** WS2812B (NeoPixel), data pin 6, ~60 LEDs, GRB color order
+- **Button:** momentary push button on pin 2, wired to GND (INPUT_PULLUP)
+- **Color format:** hex codes (`#RRGGBB`)
+- **Show loading:** compiled into firmware via Arduino IDE / arduino-cli
+
+---
+
+## Workflow
+
+```
+Write/edit .txt files in converter/shows/
+            ↓
+        make upload
+  (runs make shows → make build → arduino-cli upload)
+            ↓
+   Show starts immediately, button navigates
+```
+
+---
+
+## Design principles
+
+- **Small, clearly named functions** — each function does one thing.
+- **Comments explain the why** — not the what.
+- **PROGMEM for all show data** — Arduino Uno has only 2KB RAM; all `Step` arrays and the `SHOWS[]` index live in flash.
+- **Single config file** — all hardware values are in `config.h`; porting to a different board or strip type requires edits in one place.
+- **generate-don't-maintain** — `shows.h` and `show_*.h` are generated files; the source of truth is the `.txt` files in `converter/shows/`.
+
+---
+
+## Future ideas (not yet implemented)
+
+- Per-LED patterns (chase, sparkle, gradient segments)
+- Multiple strip support
+- Battery power optimization (auto-dim, sleep)
+- SD card loading (no recompile needed for new shows)
+- WiFi loading via ESP32 (browser-based show upload)
+- Multiple buttons for direct show selection
+- Show name displayed on a small OLED