Seedbox v0.1 + firmware, generic kit/synth, ROOT/SCALE pages

First commit of the repo. Contents beyond the v0.1 simulator and layout:

- Full Pico 2 W firmware (firmware/app, drivers, engine port, host test).
- BANK page and 404 mode A/B removed; learned pads play exactly what was learned.
- 404/MiniFreak renamed to KIT/SYNTH throughout (jacks, code, sim, docs,
  layout labels; wiring rebuilt).
- ROLL returns to page select after a re-roll; a freshly learned track turns on.
- LCD contrast 66.
- ROOT and SCALE pages: 21 scales, AUTO = the seed picks; global and sticky.

Intended music change: the scale table grew from 8 to 21 and AUTO picks from
all of them, so every seed's scale changed. Vectors regenerated with
npm run vectors, plus new key-override cases. Flash record is now version 2.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

firmware/drivers/pcd8544.h

@@ -0,0 +1,19 @@
+/* Nokia 5110 (PCD8544) on SPI0: SCK GP18, MOSI GP19, CE GP17, D/C GP20, RST GP21. 84 × 48, 504-byte framebuffer. */
+#ifndef SEEDBOX_PCD8544_H
+#define SEEDBOX_PCD8544_H
+
+#define LCD_W 84
+#define LCD_H 48
+#define LCD_VOP_DEFAULT 66     /* contrast; varies between modules, so it's a setting. 66 suits the bench module. */
+
+void lcd_init(int vop);
+void lcd_set_vop(int vop);     /* 0..127 */
+void lcd_clear(void);
+void lcd_px(int x, int y, int on);
+void lcd_fill(int x, int y, int w, int h, int on);
+void lcd_box(int x, int y, int w, int h);     /* 1 px outline */
+void lcd_text(int x, int y, const char *s);   /* 5 × 7 font from app.js, 6 px per character, upper case */
+void lcd_text_v(int x, int y, const char *s, int on);   /* draws only the glyph pixels, in on (0 = inverse) */
+void lcd_flush(void);
+
+#endif