feat: 初始提交 LeonOS 实现

添加 LeonOS 的基本实现，包括：
- 核心 API 模块（colors, disk, gps, keys, multishell, parallel, rednet, redstone, settings, vector）
- 命令行程序（about, alias, bg, clear, copy, delete, edit, fg, help, list, lua, mkdir, move, paint, peripherals, programs, reboot, set, shutdown, threads）
- 系统启动脚本和包管理
- 文档（README.md, LICENSE）
- 开发工具（devbin）和更新程序

实现功能：
- 完整的线程管理系统
- 兼容 ComputerCraft 的 API 设计
- 改进的 shell 和命令补全系统
- 多标签终端支持
- 设置管理系统

data/computercraft/lua/rom/apis/paintutils.lua

@@ -0,0 +1,158 @@
+-- rc.paintutils
+
+local term = require("term")
+local expect = require("cc.expect").expect
+local textutils = require("textutils")
+
+local p = {}
+
+function p.parseImage(str)
+  expect(1, str, "string")
+  return textutils.unserialize(str)
+end
+
+function p.loadImage(path)
+  expect(1, path, "string")
+  local handle = io.open(path)
+  if handle then
+    local data = handle:read("a")
+    handle:close()
+    return p.parseImage(data)
+  end
+end
+
+function p.drawPixel(x, y, color)
+  expect(1, x, "number")
+  expect(2, y, "number")
+  expect(2, color, "number", "nil")
+  if color then term.setBackgroundColor(color) end
+  term.at(x, y).write(" ")
+end
+
+local function drawSteep(x0, y0, x1, y1, color)
+  local distX = x1 - x0
+  local distY = y1 - y0
+
+  local diff = 2*distX - distY
+
+  local x = x0
+  for y=y0, y1, 1 do
+    p.drawPixel(x, y, color)
+    if diff > 0 then
+      x = x + 1
+      diff = diff + 2 * (distX - distY)
+    else
+      diff = diff + 2*distX
+    end
+  end
+end
+
+local function drawShallow(x0, y0, x1, y1, color)
+  local distX, distY = x1 - x0, y1 - y0
+  local diff = 2*distY - distX
+  local y = y0
+
+  for x=x0, x1, 1 do
+    p.drawPixel(x, y, color)
+    if diff > 0 then
+      y = y + 1
+      diff = diff - 2*distX
+    end
+    diff = diff + 2*distY
+  end
+end
+
+
+function p.drawLine(_startX, _startY, _endX, _endY, color)
+  expect(1, _startX, "number")
+  expect(2, _startY, "number")
+  expect(3, _endX, "number")
+  expect(4, _endY, "number")
+  expect(5, color, "number")
+  local startX, startY, endX, endY =
+    math.min(_startX, _endX), math.min(_startY, _endY),
+    math.max(_startX, _endX), math.max(_startY, _endY)
+
+  if startX == endX and startY == endY then
+    return p.drawPixel(startX, startY, color)
+  elseif startX == endX then
+    if color then term.setBackgroundColor(color) end
+    for y=startY, endY, 1 do
+      term.at(startX, y).write(" ")
+    end
+  elseif startY == endY then
+    if color then term.setBackgroundColor(color) end
+    term.at(startX, startY).write((" "):rep(endX - startX))
+  end
+
+  if (endY - startY) < (endX - startX) then
+    drawShallow(startX, startY, endX, endY)
+  else
+    drawSteep(startX, startY, endX, endY)
+  end
+end
+
+function p.drawBox(startX, startY, endX, endY, color)
+  expect(1, startX, "number")
+  expect(2, startY, "number")
+  expect(3, endX, "number")
+  expect(4, endY, "number")
+  expect(5, color, "number")
+
+  local col = string.format("%x", math.floor(math.log(color, 2)))
+  local ht, hc = (" "):rep(endX-startX+1), col:rep(endX-startX+1)
+
+  term.at(startX, startY).blit(ht, hc, hc)
+  for i=startY, endY do
+    term.at(startX, i).blit(" ", col, col)
+    term.at(endX, i).blit(" ", col, col)
+  end
+  term.at(startX, endY).blit(ht, hc, hc)
+end
+
+function p.drawFilledBox(startX, startY, endX, endY, color)
+  expect(1, startX, "number")
+  expect(2, startY, "number")
+  expect(3, endX, "number")
+  expect(4, endY, "number")
+  expect(5, color, "number")
+
+  local col = string.format("%x", math.floor(math.log(color, 2)))
+  local ht, hc = (" "):rep(endX-startX+1), col:rep(endX-startX+1)
+
+  for y=startY, endY, 1 do
+    term.at(startX, y).blit(ht, hc, hc)
+  end
+end
+
+function p.drawImage(img, x, y, frame)
+  expect(1, img, "table")
+  expect(2, x, "number")
+  expect(3, y, "number")
+  expect(4, frame, "number", "nil")
+
+  frame = frame or 1
+  if not img[frame] then
+    return nil, "invalid frame index " .. frame
+  end
+
+  if img.palette then
+    for k, v in pairs(img.palette) do
+      term.setPaletteColor(k, table.unpack(v))
+    end
+  end
+
+  if img[frame].palette then
+    for k, v in pairs(img[frame].palette) do
+      term.setPaletteColor(k, table.unpack(v))
+    end
+  end
+
+  for i, line in ipairs(img[frame]) do
+    term.at(x+i-1, y).blit(table.unpack(line))
+  end
+
+  return true
+end
+
+return p