refactor: ssr-*.cfg files are user-owned after creation

ssr mackup scan now only suggests NEW files — it never overwrites an
existing ssr-*.cfg. Once created, the file belongs to the user who
edits it directly in ~/.mackup/ to customise which paths are backed up.

- _ssr_mackup_write_cfg: returns early if file already exists
- scan: drops UPD logic; only shows NEW suggestions
- _ssr_mackup_resolve_paths: removed SSR_MACKUP_SELECTIVE_PATHS support
  (ssr.conf config variable removed — edit the cfg files instead)
- Scan output: hints to edit files directly after creation

Co-authored-by: Cursor <cursoragent@cursor.com>

bin/ssr-mackup

@@ -85,26 +85,16 @@ cmd_scan() {
         _is_declared "$stale_path" && to_remove+=("$stale_cfg")
     done
 
-    # Classify each candidate: NEW or UPD (content differs from existing).
+    # Only suggest items that have NO cfg file yet.
+    # Existing files are user-owned — edit them directly in ~/.mackup/.
     local -a to_write=()
-    local -a labels=()
     local -a cfg_paths=()
 
-    local it app_name desired existing cfg_file paths_block
+    local it app_name cfg_file
     for it in "${items[@]:-}"; do
         app_name="$(_ssr_mackup_cfg_name "$it")"
         cfg_file="$cfg_dir/${app_name}.cfg"
-        paths_block="$(_ssr_mackup_resolve_paths "$it")"
-        desired="$(printf '[application]\nname = %s\n\n[configuration_files]\n%s\n' "$app_name" "$paths_block")"
-        if [[ -f "$cfg_file" ]]; then
-            existing="$(cat "$cfg_file")"
-            if [[ "$existing" == "$desired" ]]; then
-                continue   # already up-to-date, skip
-            fi
-            labels+=("UPD")
-        else
-            labels+=("NEW")
-        fi
+        [[ -f "$cfg_file" ]] && continue   # user owns it — skip
         to_write+=("$it")
         cfg_paths+=("$cfg_file")
     done
@@ -120,22 +110,20 @@ cmd_scan() {
         printf '\nSuggested Mackup app definitions:\n'
         local i
         for i in "${!to_write[@]}"; do
-            local label="${labels[$i]}"
             local path="${cfg_paths[$i]##*/}"
-            local colour
-            [[ "$label" == "NEW" ]] && colour="\033[32m" || colour="\033[33m"
-            # Show resolved paths (selective or whole dir).
+            # Show resolved paths (selective default or whole dir).
             local resolved; resolved="$(_ssr_mackup_resolve_paths "${to_write[$i]}")"
             local line_count; line_count="$(printf '%s\n' "$resolved" | wc -l | tr -d ' ')"
             local paths_hint
             if [[ "$line_count" -eq 1 && "$resolved" == "${to_write[$i]}" ]]; then
-                paths_hint="${to_write[$i]}/"   # whole directory
+                paths_hint="${to_write[$i]}/"
             else
                 paths_hint="$line_count sub-path(s) of ${to_write[$i]}/"
             fi
-            printf "  ${colour}%s\033[0m  %-38s  %s\n" \
-                "$label" "~/.mackup/$path" "$paths_hint"
+            printf "  \033[32mNEW\033[0m  %-38s  %s\n" \
+                "~/.mackup/$path" "$paths_hint"
         done
+        printf '\n\033[2mEdit the generated files directly in ~/.mackup/ to customise paths.\033[0m\n'
     fi
 
     if [[ ${#to_remove[@]} -gt 0 ]]; then
@@ -151,7 +139,7 @@ cmd_scan() {
     local total=$(( ${#to_write[@]} + ${#to_remove[@]} ))
     ssr::confirm "Apply $total change(s)?" 60 || { printf 'Aborted.\n'; return 0; }
 
-    # Write new/updated files.
+    # Write new files (never overwrites existing ones).
     for it in "${to_write[@]:-}"; do
         _ssr_mackup_write_cfg "$cfg_dir" "$it"
     done
@@ -163,7 +151,8 @@ cmd_scan() {
     done
 
     ssr::ok "Done — ${#to_write[@]} written, ${#to_remove[@]} removed."
-    printf '\nRun \033[1mssr sync\033[0m to back up with the new definitions.\n\n'
+    printf '\nEdit ~/.mackup/ssr-*.cfg directly to customise paths.\n'
+    printf 'Run \033[1mssr sync\033[0m to back up with the new definitions.\n\n'
 }
 
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