feat: Resumable Download Helper and Manifest Preservation

- Route downloads through local cache directory
- Automatically resume interrupted downloads from the byte offset
- `setup_uninstaller_context` checks if a fail had happened. If yes then
  CLI preserves existing manifest instead of wiping it.
- Interruption Signal Traps and Prompts

lib/common.sh

@@ -84,9 +84,46 @@ version_lt() {
     done
     return 1
 }
+# Cached and resumable download helper
+download_file() {
+    local url="$1"
+    local dest="$2"
+    local cache_dir="$HOME/.local/state/bootstrap/cache"
+    
+    mkdir -p "$cache_dir"
+    
+    local safe_name
+    if has_command md5sum; then
+        safe_name=$(echo -n "$url" | md5sum | cut -d' ' -f1)
+    elif has_command shasum; then
+        safe_name=$(echo -n "$url" | shasum | cut -d' ' -f1)
+    else
+        safe_name=$(echo -n "$url" | tr -c '[:alnum:]_.-' '_')
+    fi
+    
+    local base_name
+    base_name=$(basename "$url")
+    local cache_file="$cache_dir/${safe_name}_${base_name}"
+    
+    log_info "Downloading $base_name (resumable)..."
+    if ! curl -fL -C - "$url" -o "$cache_file"; then
+        local exit_code=$?
+        # Exit code 33: HTTP server doesn't support ranges/resuming
+        # Exit code 36: Bad download resume offset
+        if [ $exit_code -eq 33 ] || [ $exit_code -eq 36 ]; then
+            log_warn "Server does not support resuming. Retrying from scratch..."
+            rm -f "$cache_file"
+            curl -fL "$url" -o "$cache_file" || return 1
+        else
+            return $exit_code
+        fi
+    fi
+    
+    mkdir -p "$(dirname "$dest")"
+    cp "$cache_file" "$dest"
+}
 
 # Export functions and variables for subshells
 export _LIB_COMMON_SOURCED=1
 export RED GREEN YELLOW BLUE NC
-export -f require_bash log_info log_success log_warn log_error confirm has_command make_temp_dir version_lt
-
+export -f require_bash log_info log_success log_warn log_error confirm has_command make_temp_dir version_lt download_file

lib/rollback.sh

@@ -20,8 +20,16 @@ setup_uninstaller_context() {
     local tool="$1"
     export BOOTSTRAP_CURRENT_TOOL="$tool"
     export BOOTSTRAP_UNINSTALLER_CMDS="$BOOTSTRAP_UNINSTALLERS_DIR/${tool}.cmds"
-    # Ensure fresh manifest for this run
-    rm -f "$BOOTSTRAP_UNINSTALLER_CMDS"
+    
+    # If a manifest already exists and the tool is NOT marked as successfully installed
+    # in history.log, we treat this as a resumed run. We preserve the manifest so
+    # that new commands are prepended to the existing ones.
+    if [ -f "$BOOTSTRAP_UNINSTALLER_CMDS" ] && ! grep -q "^INSTALL: $tool$" "$BOOTSTRAP_HISTORY_LOG" 2>/dev/null; then
+        log_info "Resuming installation of '$tool'. Preserving existing rollback manifest."
+    else
+        # Fresh installation or reinstall, start with a clean slate
+        rm -f "$BOOTSTRAP_UNINSTALLER_CMDS"
+    fi
     touch "$BOOTSTRAP_UNINSTALLER_CMDS"
 }
 

lib/routes.sh

@@ -114,11 +114,54 @@ run_ware() {
     # Run the script (edited or unchanged)
     log_info "Running ${display_name} installer..."
     setup_uninstaller_context "$tool"
+    
+    # Set trap for signals to intercept interruption and allow user to choose rollback/keep
+    local interrupted=false
+    trap 'interrupted=true' INT TERM
+    
     bash "$temp_script" "${cmd_args[@]}"
     local run_status=$?
     
-    if [ "$run_status" -eq 0 ]; then
+    # Restore default traps
+    trap - INT TERM
+    
+    if [ "$run_status" -eq 0 ] && [ "$interrupted" = "false" ]; then
         mark_install_success "$tool"
+    else
+        echo
+        if [ "$interrupted" = "true" ]; then
+            log_error "Installation of ${display_name} was interrupted."
+            run_status=130
+        else
+            log_error "Installation of ${display_name} failed with exit code $run_status."
+        fi
+        
+        local choice=""
+        if [ -t 0 ]; then
+            while true; do
+                read -r -p "Would you like to [r]ollback partial changes, or [k]eep them to resume/debug later? (r/k): " choice </dev/tty || choice="r"
+                case "$choice" in
+                    [Rr]*)
+                        execute_rollback "$tool"
+                        run_status=1
+                        break
+                        ;;
+                    [Kk]*)
+                        log_info "Keeping partial changes. Run 'b ${tool}' again to resume."
+                        run_status=1
+                        break
+                        ;;
+                    *)
+                        echo "Invalid choice. Please enter 'r' or 'k'."
+                        ;;
+                esac
+            done
+        else
+            # Non-interactive environment, default to safe rollback
+            log_warn "Non-interactive shell detected. Defaulting to automatic rollback to keep system clean."
+            execute_rollback "$tool"
+            run_status=1
+        fi
     fi
     
     # Cleanup