Add backup/restore, daily auto-backup and history CSV/JSON export (Phase E3)

- create_backup writes a zip (manifest with sha256 per file, a VACUUM INTO database snapshot, assets, archive, fonts) atomically. restore_backup validates the manifest, rejects tampered files, path traversal, symlinks and newer schemas, checks the staged DB with integrity_check, then stages a pending restore. The swap runs on the next start before the database opens, moves the current data to backups/pre-restore-<ts>/ and rolls back on any failure.
- Daily automatic backup (migration M9 auto_backup, default on) keeps the newest 14 and never blocks startup.
- Settings Data tab: back up now, restore with confirmation and restart, auto-backup toggle, last backup time.
- History exports the filtered rows as CSV (UTF-8 BOM, CRLF, formula-injection guard) or JSON (voiced.history.v1) with CA-friendly tax columns from a new list_invoice_ledger command.
- Rust round-trip, rejection, swap-rollback and retention tests; vitest for the export and backup helpers.

Adds the zip 8.6.0 and typed-path 0.12.3 crates (pure Rust); package builds must vendor them. PDF output and fingerprint goldens are unchanged. The new UI has not been run in a webview yet.

src/styles/carbon.scss

@@ -541,6 +541,26 @@ body {
   font-size: 0.75rem;
 }
 
+/* ---------- Settings: Data tab ---------- */
+.voiced-section-title {
+  font-size: 1.25rem;
+  font-weight: 400;
+  margin-bottom: 0.5rem;
+}
+
+.voiced-actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.75rem;
+  margin-top: 1rem;
+}
+
+.voiced-list {
+  margin-left: 1.25rem;
+  list-style: disc;
+}
+
 /* ---------- Invoice history and detail ---------- */
 .voiced-num {
   text-align: right;
@@ -578,6 +598,14 @@ body {
   margin-bottom: 1rem;
 }
 
+.voiced-history__export {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 1rem;
+}
+
 .voiced-history__row {
   cursor: pointer;
 }