feat: auto-generate ~/.mackup/ssr-custom.cfg for uncovered dot-dirs

Before each `ssr sync`, scan $HOME for dot-dirs/files not yet present
in the Mackup backup directory and write them into
~/.mackup/ssr-custom.cfg. This covers tools like .claude, .cursor,
.easymcp, .codex, .factory, and any future dot-dir without requiring
the user to write manual Mackup app definitions.

Curated list handles common developer tools; auto-discovery adds the
rest while skipping caches, credential dirs (.ssh, .gnupg, .aws,
.azure) and other volatile state.

Configurable via:
  SSR_MACKUP_AUTODISCOVER=true   (opt-out with false)
  SSR_MACKUP_EXTRA_PATHS="..."   (space-separated $HOME-relative paths)

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

bin/ssr-sync

@@ -46,6 +46,12 @@ ssr::brew::upgrade
 # Timeout (seconds) is configurable; default 180s.
 ssr::icloud::wait "$mackup_dir" "${SSR_ICLOUD_WAIT_TIMEOUT:-180}"
 
+# Auto-generate ~/.mackup/ssr-custom.cfg for dot-dirs not yet covered by
+# Mackup's built-in definitions (e.g. .claude, .cursor, .easymcp, …).
+if [[ "${SSR_MACKUP_AUTODISCOVER:-true}" == "true" ]]; then
+    ssr::mackup::generate_custom_cfg "$mackup_dir"
+fi
+
 ssr::mackup::backup
 ssr::brew::dump "$backup_dir"
 ssr::brew::cleanup