refactor: restructure installation to modular architecture

- Remove monolithic bootstrap.sh in favor of modular design
- Add install.sh as new main entry point with improved UX
- Split functionality into focused modules:
  - lib/common.sh: shared utilities and environment detection
  - lib/packages.sh: base system packages
  - lib/neovim.sh: Neovim and LazyVim setup
  - lib/arduino.sh: Arduino CLI and board cores
  - lib/git.sh: Git and Lazygit configuration
  - lib/shell-config.sh: Zsh and shell environment
  - lib/starship.sh: Starship prompt setup
  - lib/zellij.sh: Zellij terminal multiplexer
  - lib/scaffold.sh: project scaffolding utilities
- Update README with new installation instructions and architecture
- Improve error handling and user feedback across modules
- Maintain compatibility with both Arch Linux and Ubuntu/WSL2

This modular approach enables better maintainability, testing,
and allows users to selectively run components as needed.

lib/scaffold.sh

@@ -0,0 +1,138 @@
+#!/bin/bash
+# Step 9: Project scaffolding tool + templates
+
+step "9/9 — Creating project scaffolding tool"
+
+mkdir -p ~/.local/bin ~/.config/archduino/templates
+
+cat >~/.local/bin/arduino-new <<'SCAFFOLD'
+#!/bin/bash
+set -e
+
+TEMPLATE_DIR="$HOME/.config/archduino/templates"
+
+declare -A FQBN_MAP=(
+  ["uno"]="arduino:avr:uno"
+  ["mega"]="arduino:avr:mega"
+  ["nano"]="arduino:avr:nano"
+  ["esp32"]="esp32:esp32:esp32"
+  ["esp32s3"]="esp32:esp32:esp32s3"
+  ["esp8266"]="esp8266:esp8266:nodemcuv2"
+)
+
+usage() {
+  echo "Usage: arduino-new <project-name> <board>"
+  echo ""
+  echo "Available boards:"
+  for board in "${!FQBN_MAP[@]}"; do
+    printf "  %-12s %s\n" "$board" "${FQBN_MAP[$board]}"
+  done
+  exit 1
+}
+
+[[ $# -lt 2 ]] && usage
+
+PROJECT="$1"
+BOARD="$2"
+FQBN="${FQBN_MAP[$BOARD]}"
+
+[[ -z "$FQBN" ]] && echo "Unknown board: $BOARD" && usage
+
+mkdir -p "$PROJECT"
+cd "$PROJECT"
+
+if [[ -f "$TEMPLATE_DIR/$BOARD.ino" ]]; then
+  cp "$TEMPLATE_DIR/$BOARD.ino" "$PROJECT.ino"
+else
+  cp "$TEMPLATE_DIR/default.ino" "$PROJECT.ino"
+fi
+
+cat > sketch.yaml <<EOF
+default_fqbn: $FQBN
+default_port: auto
+EOF
+
+cat > .clangd <<EOF
+CompileFlags:
+  Add:
+    - -xc++
+    - -std=c++17
+EOF
+
+cat > .gitignore <<EOF
+build/
+.cache/
+*.elf
+*.hex
+*.bin
+EOF
+
+git init -q
+echo "✓ Created '$PROJECT' for $BOARD ($FQBN)"
+echo "  cd $PROJECT && nvim $PROJECT.ino"
+SCAFFOLD
+chmod +x ~/.local/bin/arduino-new
+
+# Templates
+cat >~/.config/archduino/templates/default.ino <<'INO'
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) { ; }
+  Serial.println("Hello from Arduino!");
+}
+
+void loop() {
+  // Your code here
+}
+INO
+
+cat >~/.config/archduino/templates/esp32.ino <<'INO'
+#include <WiFi.h>
+
+const char* ssid = "YOUR_SSID";
+const char* password = "YOUR_PASS";
+
+void setup() {
+  Serial.begin(115200);
+  delay(1000);
+  WiFi.begin(ssid, password);
+  Serial.print("Connecting to WiFi");
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println();
+  Serial.print("Connected! IP: ");
+  Serial.println(WiFi.localIP());
+}
+
+void loop() {
+  delay(1000);
+}
+INO
+
+cat >~/.config/archduino/templates/esp8266.ino <<'INO'
+#include <ESP8266WiFi.h>
+
+const char* ssid = "YOUR_SSID";
+const char* password = "YOUR_PASS";
+
+void setup() {
+  Serial.begin(115200);
+  delay(1000);
+  WiFi.begin(ssid, password);
+  Serial.print("Connecting to WiFi");
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println();
+  Serial.print("Connected! IP: ");
+  Serial.println(WiFi.localIP());
+}
+
+void loop() {
+  delay(1000);
+}
+INO
+info "Scaffolding tool + templates created"