Initial ssr repository

Convert the legacy system_sync.sh and system_restore.sh into a modular
shareable repository:

- bin/ssr CLI dispatcher with install/sync/restore/schedule/config/status
- lib/ split: common, cloud, brew, mackup, macos
- Cloud provider abstraction (icloud, dropbox, googledrive, onedrive, custom)
- launchd template for scheduled daily sync (renderable via sed)
- ssr.conf.example with whitelisted KEY=VALUE config loader
- macos-defaults.sh extracted from inline block, overridable
- install.sh bootstrap symlinks CLI into ~/.local/bin
- README with usage, config table, migration map, security notes
- Original scripts archived under legacy/ for reference

Fixes vs originals: set -euo pipefail, quoted vars, find -print0,
spctl --global-disable (was --master-disable), MACOS=".macos" bug,
zero-width char before ln, Apple Silicon brew shellenv, config injection
hardening.

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

bin/ssr-config

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# ssr-config — show or edit the active configuration file.
+
+set -euo pipefail
+SSR_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck source=../lib/common.sh
+source "$SSR_ROOT/lib/common.sh"
+
+cfg="${SSR_CONFIG:-$HOME/.config/ssr/ssr.conf}"
+
+case "${1:-show}" in
+    show)
+        if [[ -f "$cfg" ]]; then
+            echo "# $cfg"
+            cat "$cfg"
+        else
+            ssr::warn "No config found at $cfg"
+            echo "Run: ssr install   to seed one from the example."
+            exit 1
+        fi
+        ;;
+    edit)
+        ssr::ensure_dir "$(dirname "$cfg")"
+        if [[ ! -f "$cfg" ]]; then
+            cp "$SSR_ROOT/config/ssr.conf.example" "$cfg"
+            chmod 600 "$cfg"
+        fi
+        "${EDITOR:-vi}" "$cfg"
+        ;;
+    path)
+        echo "$cfg"
+        ;;
+    *)
+        ssr::die "Usage: ssr config [show|edit|path]"
+        ;;
+esac