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-tauri/Cargo.lock

@@ -4188,6 +4188,12 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
+[[package]]
+name = "typed-path"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e28f89b80c87b8fb0cf04ab448d5dd0dd0ade2f8891bae878de66a75a28600e"
+
 [[package]]
 name = "typeid"
 version = "1.0.3"
@@ -4307,6 +4313,7 @@ dependencies = [
  "tempfile",
  "thiserror 2.0.21",
  "uuid",
+ "zip",
 ]
 
 [[package]]
@@ -5182,6 +5189,19 @@ dependencies = [
  "syn 3.0.6",
 ]
 
+[[package]]
+name = "zip"
+version = "8.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d04a6b5381502aa6087c94c669499eb1602eb9c5e8198e534de571f7154809b"
+dependencies = [
+ "crc32fast",
+ "flate2",
+ "indexmap 2.14.2",
+ "memchr",
+ "typed-path",
+]
+
 [[package]]
 name = "zlib-rs"
 version = "0.6.8"

src-tauri/Cargo.toml

@@ -28,6 +28,7 @@ thiserror = "2"
 base64 = "0.22"
 sha2 = "0.10"
 flate2 = "1"
+zip = { version = "8", default-features = false, features = ["deflate-flate2"] }
 percent-encoding = "2"
 image = { version = "0.25.10", default-features = false, features = ["png", "jpeg", "webp"] }
 

src-tauri/src/commands/invoice.rs

@@ -546,6 +546,83 @@ pub fn list_invoices_impl(conn: &Connection) -> Result<Vec<InvoiceSummary>, Stri
     Ok(rows)
 }
 
+/// What the History export needs beyond `InvoiceSummary`: the tax split and CA-facing fields, all money as
+/// integer paise. Joined to the list rows by `id` on the TypeScript side.
+#[derive(Debug, Clone, serde::Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct InvoiceLedgerRow {
+    pub id: i64,
+    pub client_gstin: String,
+    pub place_of_supply_code: String,
+    pub doc_type: String,
+    /// Distinct non-empty HSN/SAC codes of the lines, in line order.
+    pub hsn_sac: Vec<String>,
+    /// Subtotal less discount.
+    pub taxable_paise: i64,
+    pub cgst_paise: i64,
+    pub sgst_paise: i64,
+    pub igst_paise: i64,
+    pub reverse_charge: bool,
+}
+
+pub fn list_invoice_ledger_impl(conn: &Connection) -> Result<Vec<InvoiceLedgerRow>, String> {
+    let mut hsn_by_invoice: std::collections::HashMap<i64, Vec<String>> = std::collections::HashMap::new();
+    {
+        let mut stmt = conn
+            .prepare("SELECT invoice_id, TRIM(hsn_sac) FROM invoice_items ORDER BY invoice_id, sort_order, id")
+            .map_err(|e| e.to_string())?;
+        let items = stmt
+            .query_map([], |r| Ok((r.get::<_, i64>(0)?, r.get::<_, String>(1)?)))
+            .map_err(|e| e.to_string())?;
+        for item in items {
+            let (id, code) = item.map_err(|e| e.to_string())?;
+            let list = hsn_by_invoice.entry(id).or_default();
+            if !code.is_empty() && !list.contains(&code) {
+                list.push(code);
+            }
+        }
+    }
+    let mut stmt = conn
+        .prepare(
+            "SELECT id, client_gstin, place_of_supply_state_code, doc_type, subtotal, discount,
+                    cgst_amount, sgst_amount, igst_amount, reverse_charge
+             FROM invoices ORDER BY id DESC",
+        )
+        .map_err(|e| e.to_string())?;
+    let rows = stmt
+        .query_map([], |r| {
+            let id: i64 = r.get(0)?;
+            Ok(InvoiceLedgerRow {
+                id,
+                client_gstin: r.get(1)?,
+                place_of_supply_code: r.get(2)?,
+                doc_type: r.get(3)?,
+                hsn_sac: Vec::new(),
+                taxable_paise: gst::rupees_to_paise(r.get(4)?) - gst::rupees_to_paise(r.get(5)?),
+                cgst_paise: gst::rupees_to_paise(r.get(6)?),
+                sgst_paise: gst::rupees_to_paise(r.get(7)?),
+                igst_paise: gst::rupees_to_paise(r.get(8)?),
+                reverse_charge: r.get::<_, i64>(9)? != 0,
+            })
+        })
+        .map_err(|e| e.to_string())?
+        .collect::<rusqlite::Result<Vec<_>>>()
+        .map_err(|e| e.to_string())?;
+    Ok(rows
+        .into_iter()
+        .map(|mut row| {
+            row.hsn_sac = hsn_by_invoice.remove(&row.id).unwrap_or_default();
+            row
+        })
+        .collect())
+}
+
+#[tauri::command]
+pub fn list_invoice_ledger(state: State<AppState>) -> Result<Vec<InvoiceLedgerRow>, String> {
+    let conn = state.db.lock().map_err(|e| e.to_string())?;
+    list_invoice_ledger_impl(&conn)
+}
+
 pub fn get_invoice_impl(conn: &Connection, id: i64) -> Result<Invoice, String> {
     fetch_invoice(conn, id).map_err(|e| e.to_string())
 }
@@ -696,6 +773,28 @@ mod tests {
         conn.query_row("SELECT COUNT(*) FROM invoices", [], |r| r.get(0)).unwrap()
     }
 
+    #[test]
+    fn ledger_rows_carry_the_tax_split_in_paise_and_distinct_hsn() {
+        let mut conn = registered();
+        let first = issue(&mut conn, input(json!({"placeOfSupplyStateCode": "27"}))).unwrap();
+        conn.execute("UPDATE invoice_items SET hsn_sac = ' 9983 ' WHERE invoice_id = ?1", params![first.id]).unwrap();
+        conn.execute(
+            "INSERT INTO invoice_items (invoice_id, description, amount, sort_order, hsn_sac) VALUES (?1, 'b', 1, 5, '9983'), (?1, 'c', 1, 6, '9984'), (?1, 'd', 1, 7, '')",
+            params![first.id],
+        )
+        .unwrap();
+        let ledger = list_invoice_ledger_impl(&conn).unwrap();
+        assert_eq!(ledger.len(), 1);
+        let row = &ledger[0];
+        assert_eq!(row.id, first.id);
+        assert_eq!(row.place_of_supply_code, "27");
+        assert_eq!(row.doc_type, "tax_invoice");
+        assert_eq!(row.hsn_sac, vec!["9983".to_string(), "9984".to_string()]);
+        assert_eq!(row.taxable_paise, 731_000);
+        assert_eq!((row.cgst_paise, row.sgst_paise, row.igst_paise), (65_790, 65_790, 0));
+        assert!(!row.reverse_charge);
+    }
+
     #[test]
     fn issues_numbered_tax_invoices_with_derived_totals() {
         let mut conn = registered();

src-tauri/src/commands/mod.rs

@@ -1,5 +1,6 @@
 pub mod archive;
 pub mod assets;
+pub mod backup;
 pub mod clients;
 pub mod files;
 pub mod fonts;

src-tauri/src/db.rs

@@ -10,7 +10,7 @@ const MAX_BACKUPS: usize = 10;
 const BACKUP_PREFIX: &str = "voiced-pre-v";
 
 /// Highest schema version, i.e. the number of entries in `migrations()`.
-const LATEST_VERSION: i64 = 8;
+pub(crate) const LATEST_VERSION: i64 = 9;
 
 #[derive(Debug, thiserror::Error)]
 pub enum DbError {
@@ -264,6 +264,12 @@ CREATE TABLE payments (
 CREATE INDEX idx_payments_invoice ON payments(invoice_id);
 "#;
 
+/// Version 9: `auto_backup` switches the daily automatic backup (see commands::backup). On by default. It is read and
+/// written through its own commands, not through `Settings`, so a settings save can never clobber it.
+const M9: &str = r#"
+ALTER TABLE app_settings ADD COLUMN auto_backup INTEGER NOT NULL DEFAULT 1;
+"#;
+
 fn migrations() -> Migrations<'static> {
     Migrations::new(vec![
         M::up(SCHEMA),
@@ -274,6 +280,7 @@ fn migrations() -> Migrations<'static> {
         M::up(M6),
         M::up(M7),
         M::up(M8),
+        M::up(M9),
     ])
 }
 
@@ -294,7 +301,14 @@ pub fn open(path: &Path, backup_dir: &Path) -> Result<Connection, DbError> {
     Ok(conn)
 }
 
-fn has_user_tables(conn: &Connection) -> rusqlite::Result<bool> {
+/// Write a consistent, compacted snapshot of the open database to `target` (which must not exist yet).
+/// Safe while other connections read and write: SQLite takes a read transaction for the copy.
+pub(crate) fn vacuum_into(conn: &Connection, target: &Path) -> rusqlite::Result<()> {
+    let quoted = target.to_string_lossy().replace('\'', "''");
+    conn.execute_batch(&format!("VACUUM INTO '{quoted}'"))
+}
+
+pub(crate) fn has_user_tables(conn: &Connection) -> rusqlite::Result<bool> {
     conn.query_row(
         "SELECT EXISTS (SELECT 1 FROM sqlite_master WHERE type = 'table' AND name NOT LIKE 'sqlite_%')",
         [],
@@ -312,8 +326,7 @@ fn backup_before_migration(
     fs::create_dir_all(backup_dir)?;
     let stamp = chrono::Local::now().format("%Y%m%d-%H%M%S");
     let target = backup_dir.join(format!("{BACKUP_PREFIX}{version}-{stamp}.db"));
-    let quoted = target.to_string_lossy().replace('\'', "''");
-    conn.execute_batch(&format!("VACUUM INTO '{quoted}'"))?;
+    vacuum_into(conn, &target)?;
     // A failed prune must not block startup; the backup itself already succeeded.
     let _ = prune_backups(backup_dir, MAX_BACKUPS);
     Ok(target)

src-tauri/src/lib.rs

@@ -56,6 +56,15 @@ fn init_state(app: &tauri::App) -> Result<AppState, Box<dyn std::error::Error>>
         show_startup_error(app, &format!("Could not create the local data directory: {e}"), Some(&local_data_dir));
         return Err(e.into());
     }
+    // A restore staged by the Data tab is swapped in now, before anything opens the database.
+    let dirs = commands::backup::DataDirs::new(&data_dir, &local_data_dir);
+    match commands::backup::apply_pending_restore(&dirs, chrono::Local::now()) {
+        commands::backup::ApplyOutcome::NothingPending => {}
+        commands::backup::ApplyOutcome::Applied { safety_dir } => {
+            eprintln!("Backup restored; the previous data is in {}", safety_dir.display());
+        }
+        commands::backup::ApplyOutcome::Failed { message } => eprintln!("Backup restore failed: {message}"),
+    }
     let conn = match db::open(&data_dir.join("voiced.db"), &data_dir.join("backups")) {
         Ok(conn) => conn,
         Err(e) => {
@@ -71,6 +80,7 @@ fn init_state(app: &tauri::App) -> Result<AppState, Box<dyn std::error::Error>>
     if let Err(e) = commands::logo::ensure_logo_derived_impl(&conn, &data_dir) {
         eprintln!("Could not derive the logo images: {e}");
     }
+    commands::backup::spawn_auto_backup(dirs);
     Ok(AppState {
         db: Mutex::new(conn),
         data_dir,
@@ -80,6 +90,9 @@ fn init_state(app: &tauri::App) -> Result<AppState, Box<dyn std::error::Error>>
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
+    // After "Restart" in the Data tab the new process waits for the old one (and its single-instance lock) to go.
+    commands::backup::wait_if_relaunched();
+
     // WebKitGTK's DMABUF renderer shows a blank window on several Linux GPU/driver
     // combinations. Respect an explicit user setting, otherwise turn it off.
     #[cfg(target_os = "linux")]
@@ -136,6 +149,13 @@ pub fn run() {
             commands::payments::record_payment,
             commands::payments::list_payments,
             commands::payments::delete_payment,
+            commands::backup::create_backup,
+            commands::backup::restore_backup,
+            commands::backup::cancel_pending_restore,
+            commands::backup::get_backup_status,
+            commands::backup::set_auto_backup,
+            commands::backup::restart_app,
+            commands::invoice::list_invoice_ledger,
             commands::assets::import_asset,
             commands::assets::save_asset_bytes,
             commands::assets::read_asset_data_uri,