Initial commit: Schunix as it stands before the SchOS rename

An x86-64 operating system built from xv6, now largely rewritten: SMP,
a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF
rasteriser, and a Linux-numbered syscall ABI.

No history before this point -- the tree was never under version control.
This commit exists so the rename that follows has something to undo to.

include/theme.h

@@ -0,0 +1,57 @@
+#pragma once
+
+// Schunix visual identity — one palette, shared by everything that draws.
+//
+// This header exists because there were three unrelated designs and the seams
+// showed. The bootloader splash was deep purple with gold text, deliberately
+// matching the *panic* screen; the kernel console was cream with near-black
+// text; the panic screen was the purple both were copying. So a normal boot
+// looked like a crash, then abruptly became an amber terminal, and none of the
+// three looked like the same product.
+//
+// The rule now: **normal states are calm and dark; only failure is loud.**
+// Boot, console and shell share SCH_BG/SCH_FG. The panic screen keeps the
+// full-bleed purple entirely to itself, which is what makes it mean something.
+//
+// Included by boot/stage2main.c (freestanding, pre-kernel), kernel/dev/vga.c,
+// kernel/core/console.c and kernel/core/panic.c. Plain #defines only — no
+// types, no code — because stage2 is compiled 32-bit against a different
+// world than the kernel.
+//
+// Colours are 0xRRGGBB. vga_draw_pixel packs them for whatever depth the
+// framebuffer actually is.
+
+// --- the product ---------------------------------------------------------
+// Near-black with a slight blue cast rather than pure #000: pure black on an
+// LCD reads as "the machine is off", and every serious platform sits a few
+// points above it.
+#define SCH_BG          0x0C0E13
+#define SCH_FG          0xE6E8EC   // primary text
+#define SCH_DIM         0x707784   // secondary text, hints, version strings
+#define SCH_ACCENT      0x7C5CFF   // the one accent: violet, keeping the
+                                   // project's purple lineage without the
+                                   // eye-searing chroma of the old splash
+#define SCH_ACCENT_DIM  0x2A2440   // unused track behind a progress bar
+#define SCH_OK          0x4ADE80   // reserved: success states
+#define SCH_WARN        0xFBBF24   // reserved: warnings that are not panics
+
+// --- failure -------------------------------------------------------------
+// PSOGM. Deliberately unlike anything above, because its whole job is to be
+// unmistakable. See kernel/core/panic.c.
+//
+// These are the values panic.c actually renders. It used to carry a second,
+// different set of PSOGM_* defines of its own, so the two disagreed about what
+// the crash screen looked like and this header was quietly fiction. There was
+// also a PSOGM_TITLE in gold here, left over from a splash design that no
+// longer exists -- the screen is one background and two weights of text, on
+// purpose, because a crash screen with an accent colour is a crash screen
+// someone was enjoying designing.
+#define PSOGM_BG        0x4B1D9A   // the purple
+#define PSOGM_FG        0xFFFFFF   // the face, the headline, the values
+#define PSOGM_DIM       0xC3AEEC   // labels and the closing lines
+
+// The one exception to "two weights of text": the QR card has to be a light
+// panel with dark modules, because that is what a scanner needs. It reads as a
+// label stuck onto the screen, which is roughly what it is.
+#define PSOGM_CARD      0xFFFFFF
+#define PSOGM_INK       0x000000