Start the setup wizard blank and add a Run setup again button

The first-run seed no longer inserts the original vendor's name, address, contact
details, PAN or bank account; the wizard now starts empty and requires a name and
state. Settings > Data gets a Run setup again button that clears the onboarded flag.
Re-running the wizard keeps the active invoice series unless the prefix or padding
changes. The sample logo moves out of public/ so it no longer ships in the app.

src-tauri/src/commands/invoice.rs

@@ -940,7 +940,7 @@ mod tests {
         let bank_id: i64 = conn.query_row("SELECT id FROM bank_accounts", [], |r| r.get(0)).unwrap();
         let inv = issue(&mut conn, input(json!({"bankAccountId": bank_id}))).unwrap();
         let bank: serde_json::Value = serde_json::from_str(&inv.bank_snapshot).unwrap();
-        assert_eq!(bank["bankName"], "State Bank of India");
+        assert_eq!(bank["bankName"], "Test Bank");
         let err = issue(&mut conn, input(json!({"bankAccountId": 9999}))).unwrap_err();
         assert!(err.contains("bank account"), "{err}");
     }