Zaplo v26.7.4

refactor: rebrand Deplao → Zaplo and consolidate release CI

- App identity: productName Zaplo, appId com.zaplo.app, scheme zaplo://,
  app.setName/userModelId, window title, tray, deep links
- Default DB filename → zaplo-tool.db (new standalone app data dir)
- User-facing strings, workflow bot names, README → Zaplo
- CI: single build-all workflow (Win+macOS+Linux) publishing to this repo
  with Go-built E2EE bridge per platform; remove redundant per-OS workflows

Note: infra URLs (deplaoapp.com, support repo) and data-format keys
(_deplaoWorkflow, deplao-config.json, order-source tags) kept intentionally
to avoid breaking runtime/data compatibility.