Initial project outline

- package.json (ESM, bin entry)
- bin/delta-backup.js — entrypoint
- lib/args.js — CLI arg parsing via Node parseArgs
- lib/config.js — config file merging + required path guards
- lib/spawn.js — safe process spawning (no shell strings)
- lib/state.js — sequence number + phase state management
- lib/backends/zstd.js — zstd delta backend
- lib/backends/index.js — backend registry
- lib/commands/run.js — full run skeleton (phases 1-3 wired, 4-6 stubbed)
- lib/commands/status.js — status command

package.json

@@ -0,0 +1,12 @@
+{
+  "name": "delta-backup",
+  "version": "0.1.0",
+  "type": "module",
+  "description": "Space-efficient directory backups using binary deltas",
+  "bin": {
+    "delta-backup": "./bin/delta-backup.js"
+  },
+  "scripts": {
+    "start": "node bin/delta-backup.js"
+  }
+}