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

lib/commands/status.js

@@ -0,0 +1,28 @@
+/**
+ * status command — show current state.
+ */
+import { readState, PHASES } from '../state.js';
+
+export async function statusCommand(config) {
+  const { deltas } = config;
+
+  if (!deltas) {
+    console.error('Error: --deltas required for status command');
+    process.exit(1);
+  }
+
+  const state = await readState(deltas);
+
+  console.log('\ndelta-backup status');
+  console.log('='.repeat(40));
+  console.log(`  Last complete seq:  ${state.last_complete}`);
+  console.log(`  Next seq:          ${state.next_seq}`);
+  console.log(`  Current phase:     ${state.phase}`);
+
+  if (state.phase !== PHASES.IDLE) {
+    console.log('\n  ⚠ Previous run did not complete cleanly.');
+    console.log('  Run with same options to recover.');
+  }
+
+  console.log('');
+}