feat: add Renode emulator, nvim-dap debugging, and backup collision fix

- Add Renode installation (AUR/deb) with arduino-sim helper script
  supporting STM32F4, RP2040, and nRF52840 (USB HID) platforms
- Add nvim-dap + nvim-dap-ui with GDB remote adapter for Renode debugging
- Add debug keybindings under <leader>d prefix
- Fix backup_config() path collisions when multiple sources share a
  basename (e.g. ~/.config/nvim and ~/.local/share/nvim)
- Strip NvChad starter's nvim-lspconfig block that conflicts with
  native vim.lsp.config, preserving configs/lazy.lua
- Update step counts from 11 to 12 (TOTAL_STEPS 12→13, 13→14 on WSL)

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

install.sh

@@ -82,6 +82,7 @@ source "$SCRIPT_DIR/lib/zellij.sh"
 source "$SCRIPT_DIR/lib/neovim.sh"
 source "$SCRIPT_DIR/lib/yazi.sh"
 source "$SCRIPT_DIR/lib/arduino.sh"
+source "$SCRIPT_DIR/lib/renode.sh"
 source "$SCRIPT_DIR/lib/git.sh"
 source "$SCRIPT_DIR/lib/scaffold.sh"
 source "$SCRIPT_DIR/lib/shell-config.sh"
@@ -104,6 +105,8 @@ echo "    arduino-new my-project uno    # scaffold a project"
 echo "    adev                          # launch Arduino workspace"
 echo "    <leader>av                    # compile in Neovim"
 echo "    <leader>au                    # upload in Neovim"
+echo "    arduino-sim build/fw.elf      # simulate with Renode"
+echo "    <leader>ds                    # attach debugger to Renode"
 echo "    theme                         # switch colorscheme"
 echo ""
 warn "A reboot is recommended to apply all changes (shell, groups, PATH)."