vault: autosync the personal vault to the logicsrc account (#226)

`logicsrc vault` (OpenCreds) lived only in ~/.config/logicsrc/opencreds.
Lose the machine and the vault went with it, and a second machine had
no way to get it. It now syncs to the logged-in account.

Server (apps/pwa, /api/opencreds, session or lsk_ bearer):
- opencreds_vaults: one per user. meta (key material already wrapped
  under the master password) + an encrypted folder list, each with a
  revision.
- opencreds_items: one row per item, as the spec asks; envelope NULL is
  a tombstone so purges propagate; seq for incremental pulls.
- Every write names its base revision; a stale one gets 409 with the
  current row. Writes are conditional and read back (each envelope's
  random IV identifies our write), so this needs nothing dialect-specific
  from SQLite or Postgres.
- Stores ciphertext only. The server learns item count and type codes,
  as OpenCreds security.md already accepts.

Client (@logicsrc/opencreds sync.ts, key-free except where noted):
- Pull before every vault command, push after. Offline, the command
  still works and the change goes up next time.
- Conflicts never lose data: the account's edit keeps the id and this
  machine's becomes "<name> (conflict copy)" (needs the unlocked key, so
  it waits otherwise). An edit beats a purge. Byte-identical envelopes
  are adopted, not split, so a lost sync.json is harmless.
- Two different vaults (meta.createdAt differs) are never merged:
  refused, with `vault sync --use-remote` (backs this machine's up to
  .bak-NNN) or `--use-local`.
- Remote item ids must be plain ids; anything else is ignored and never
  becomes a path.
- Folder names are AES-GCM encrypted under the user key before upload.

CLI (0.6.0): `logicsrc vault sync [--status|--use-remote|--use-local]`.
Only the default vault syncs, and only when logged in; a --home or
OPENCREDS_HOME vault stays local unless LOGICSRC_VAULT_SYNC=on;
LOGICSRC_VAULT_SYNC=off disables it. The standalone `opencreds` binary
gets no remote and never syncs. `init` on a machine that just downloaded
the account's vault says to unlock it instead of suggesting --force.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

packages/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@logicsrc/cli",
-  "version": "0.5.0",
+  "version": "0.6.0",
   "description": "LogicSRC CLI: every LogicSRC standard and tool as one command.",
   "type": "module",
   "main": "./dist/index.js",