Add PyInstaller spec and Gitea Actions CI for Linux/Windows binaries

- run.py: top-level entry point for PyInstaller (relative imports need it)
- psp-preserve.spec: onedir build bundling DATs, loader, cover bundles, icons
- requirements-build.txt: pinned build deps (PySide6 6.8.3 for Windows ICU fix)
- .gitea/workflows/build.yml: builds linux + windows artifacts on tags/manual
- gitignore build/ dist/

README.md

@@ -59,6 +59,57 @@ pip install -r requirements.txt
 python3 -m app.main
 ```
 
+## Building binaries
+
+The GUI is packaged with PyInstaller into a self-contained folder. Build
+requirements are pinned in `requirements-build.txt` (PySide6 6.8.3 on purpose —
+see the note inside).
+
+```bash
+python3 -m venv .venv-build
+. .venv-build/bin/activate
+pip install -r requirements-build.txt
+pyinstaller --clean --noconfirm psp-preserve.spec
+# output: dist/psp-preserve/  → run dist/psp-preserve/psp-preserve
+```
+
+Notes:
+
+- The build bundles the DATs, PS1 loader, and the offline cover bundles. The
+  cover zips are large (~850 MB), so builds are slow and the output is big.
+- `7z` (p7zip-full on Linux, 7-Zip on Windows) is a **runtime** dependency for
+  reading store archives — it is not bundled.
+- User data (credentials, manual covers, PS1 templates, NPS cache, library DB,
+  cover cache) lives in the OS state dir, never next to the binary.
+
+### CI (Gitea Actions)
+
+`.gitea/workflows/build.yml` builds Linux and Windows artifacts on version-tag
+pushes (`v*`) or on manual trigger (**Actions → build → Run workflow**).
+Artifacts appear on the Actions run page and can be attached to a release.
+
+Each job needs a [Gitea Actions runner](https://docs.gitea.com/usage/actions/act-runner)
+registered with the matching label:
+
+```bash
+# Linux runner (Docker mode, run on your server)
+./act_runner register \
+  --instance https://git.ceaf.dev \
+  --token <registration-token> \
+  --name linux-builder \
+  --labels ubuntu-latest:docker://node:20-bookworm
+
+# Windows runner (host mode, run on a Windows machine)
+act_runner.exe register \
+  --instance https://git.ceaf.dev \
+  --token <registration-token> \
+  --name win-builder \
+  --labels windows:host
+```
+
+The registration token is generated in Gitea under
+**Site Administration → Actions → Runners → Create new runner**.
+
 ## First-time setup
 
 1. Put your DAT files in `data/dats/`: