[lapinpt]

Adds an opt-in Windows portable mode: placing portable.flag beside the executable stores configuration in Data/trguing.json and the WebView2 profile in Data/WebView2. The WebView2 Runtime remains a system dependency. Without the marker, the existing installed configuration location is preserved.

Configuration is read and written through commands with a fixed path selected at startup. Saves are serialized and use a temporary file followed by replacement. A portable data-directory error does not silently redirect settings to the installed profile.

Includes an English migration guide, an import helper that preserves the original JSON and creates a SHA-256-verified backup, and a Windows portable ZIP workflow with source revision and binary/GeoIP hashes. The helper refuses to overwrite an existing portable configuration; packaging derives the source repository URL from its environment.

Validation

• Standalone Windows build and runtime checks: portable configuration loading/saving, WebView2 data location, relocation and unchanged installed settings.
• Four storage tests passed locally on Linux and in Windows CI: installed-path compatibility, portable isolation/relocation, concurrent saves, and invalid-marker/blocked-directory behavior.
• Import tests verify identical source/backup/destination hashes, preservation of the original, and refusal to overwrite an existing destination.
• ESLint and Linux Clippy; local production frontend build passed.

Runtime checks cover Windows x64. macOS runtime behavior has not been tested.