Maxwooow / Ricoh-GRMod

# GR Mod
A small desktop tool for the Ricoh GR IV / GR IV HDF (firmware 1.11). Not a Ricoh product.
- `core/` platform-independent TypeScript: firmware container codec and patcher with built-in self-check (`src/fw`), added aspect ratios (`src/fw/aspect`), preset conversion from .xmp Look profiles and .cube LUTs (`src/color`), exact-length baseline JPEG encoder (`src/jpeg`), start-up script generator and simulator (`src/wallpaper`; used by GR Mod 0.7 and earlier, whose power-off images rotated through a start-up script on the card; 0.8 builds them into the firmware and the UI no longer offers the script), memory-card layout planning (`src/card`), and the `Engine` facade (`src/app`).
- `ui/` React UI (Vite). Talks to the platform through `src/host.ts` only.
- `shell/` desktop shell in Go for Windows, macOS and Linux (a WebView2 window on Windows, a Chromium "app" window on macOS and Linux, plus a local HTTP API for drives and files, and for fetching the official firmware from Ricoh's site and updates of GR Mod itself). See `shell/README.md`.
Build: `npm install && npm -w ui run build && (cd shell && ./build.sh windows)` → `shell/dist/GRMod.exe`; `./build.sh mac` → `shell/dist/GR Mod.app` and `shell/dist/GRMod-mac.zip` (Intel Macs with macOS 10.13 or later, Apple silicon with macOS 11 or later), plus `GRMod- -mac.dmg` when the disk image tools are installed; `./build.sh linux` → `shell/dist/grmod` (x64).
On a Mac: unzip `GRMod-mac.zip` and move `GR Mod.app` to Applications. The app is signed ad hoc, not with an Apple Developer ID, so the first start is blocked: open System Settings › Privacy & Security and click "Open Anyway" (or run `xattr -dr com.apple.quarantine "/Applications/GR Mod.app"` once). The UI opens in a window of Chrome, Edge, Brave, Chromium or Vivaldi when one is installed, otherwise in the default browser; GR Mod quits by itself about 20 seconds after that window is closed. macOS asks once for access to removable volumes; allow it, or the card cannot be written.
On Linux: start `shell/dist/grmod`. The UI opens in an app window of Chrome, Chromium, Edge, Brave or Vivaldi when one is in `PATH`, otherwise in the default browser; GR Mod quits when that window is closed. The card is offered once the desktop has mounted it (as the file manager does, below `/run/media/ ` or `/media/ `), and Eject unmounts it with `udisksctl`. The folder dialog needs `kdialog` or `zenity`. There is no Linux release package, so this build does not update itself.
Test: `npm -w core test` (the byte-identity tests need the official firmware in `core/testdata/private/`, which is not distributed), `cd shell && go test ./... && go test -tags desktop ./...`.
An Android build would reuse `core/` and `ui/` unchanged and replace `shell/` with a WebView wrapper implementing the same host interface (volumes via the Storage Access Framework).
No firmware file is included here. The user picks the official 1.11 file, or lets the program fetch it: the shell reads Ricoh's ow