store: add NoPayStation source (PSP + PS1 Classics .pkg)

New 'NoPayStation' option in the Store tab lists PSP_GAMES.tsv and
PSX_GAMES.tsv, downloads each item's encrypted .pkg and decrypts/extracts
it with pkg2zip into a configurable output dir (<dir>/PSP/<TITLE_ID>/ and
<dir>/PSX/<TITLE_ID>/). Downloaded PSP games and PS1 Classics appear in the
Library (games/eboot and ps1/eboot respectively) and copy to the PSP as
PSP/GAME folders.

- app/nopaystation.py: TSV fetch/parse (cached) + pkg2zip discovery/extract.
- app/transfers.py: NoPayStationSource (scan + download).
- Settings: NPS output dir + pkg2zip path (QSettings nps_dir/pkg2zip_path).
- StorePage: NPS source + content-type combo (PSP Games / PS1 Classics),
  per-item cover system, TSV release dates, nps-download job kind.
- Library: _nps_library_items ingest, on-PSP detection, folder copy/delete,
  PPSSPP play disabled for encrypted PSP EBOOTs.
- README: document the source, pkg2zip + npdrm_free requirements.

README.md

@@ -1,6 +1,6 @@
 # PSP Preservation Tool
 the name is terrible, i know.
- 
+
 ![AI Generated](https://raw.githubusercontent.com/dotnetdave/ai-usage-badges/refs/heads/main/badges/png/1x/ai-generated.png)
 
 Native Linux GUI (PySide6) for preserving PSP UMD **games** and **videos** as
@@ -18,9 +18,9 @@ converts PlayStation 1 ISO/CUE/BIN rips into PSP `EBOOT.PBP` homebrew.
 - **Library** — scan folders of `.iso` discs, verify against the DAT catalog,
   browse with cover art, search/filter, see per-game details (developer,
   publisher, genre, release date, synopsis, trailer), and launch discs in PPSSPP.
-- **Store** — browse and download discs from three sources: a local 7z folder,
-  your own HTTP store server, or an archive.org item (see
-  [Store](#store--archiveorg-and-local-folder)).
+- **Store** — browse and download discs from four sources: a local 7z folder,
+  your own HTTP store server, an archive.org item, or NoPayStation (PSP/PS1
+  PSN `.pkg` content) (see [Store](#store--archiveorg-and-local-folder)).
 - **Queue** — background transfers with progress, cancel, per-row delete, etc.
 - **PSP Sync** — detect a connected PSP (USB) or a mounted UMD, inventory what's
   installed (games / UMD videos / homebrew / PKG), copy discs to the PSP, delete
@@ -38,6 +38,8 @@ converts PlayStation 1 ISO/CUE/BIN rips into PSP `EBOOT.PBP` homebrew.
 - Linux + Python 3
 - `PySide6` — the only Python dependency (`pip install -r requirements.txt`)
 - `7z` (p7zip) — used to peek/extract disc images from store archives
+- `pkg2zip` (optional) — decrypts NoPayStation `.pkg` files (see
+  [NoPayStation](#4-nopaystation))
 - PPSSPP (optional) — to launch discs from the details panel
 
 ## Install
@@ -132,6 +134,9 @@ QSettings under `PSPPreserve`) taking precedence where noted.
 | `PSP_ARCHIVE_ITEM` | `psp-redump-roms321.com` | archive.org item identifier |
 | `PSP_ARCHIVE_LOGGED_IN_SIG` | *(empty)* | archive.org `logged-in-sig` cookie |
 | `PSP_ARCHIVE_LOGGED_IN_USER` | *(empty)* | archive.org `logged-in-user` cookie |
+| `PSP_NPS_DIR` | `<state>/nps` | NoPayStation output folder |
+| `PSP_NPS_TSV_BASE` | `https://nopaystation.com/tsv/` | NoPayStation TSV base URL |
+| `PSP_PKG2ZIP_PATH` | *(empty)* | pkg2zip binary path (else auto-detected) |
 | `PSP_API_TOKEN` | *(empty)* | server API bearer token (unset = open) |
 | `PSP_CREDENTIALS` | `$PSP_DATA_DIR/credentials.json` | credentials file |
 | `PSP_LIBRETRO_COVERS_URL` | *(empty)* | direct URL for `libretro-covers.zip` (else derived from store server) |
@@ -258,6 +263,32 @@ If the item's files are marked **private** (login required), set the
 from a logged-in archive.org browser session). Without them, private files are
 skipped — and you'll get a clear error if *everything* in the item is private.
 
+### 4. NoPayStation
+
+The **NoPayStation** source lists PSN content from
+[NoPayStation](https://nopaystation.com/) — **PSP games** (`PSP_GAMES.tsv`) and
+**PS1 Classics** (`PSX_GAMES.tsv`), selectable from the content-type dropdown
+next to the source selector.
+
+Requirements & behaviour:
+
+1. Install [`pkg2zip`](https://github.com/mmozeiko/pkg2zip) (the same tool the
+   pkgi family uses) and either put it on `PATH` or set its path in
+   **Settings → Store**. NoPayStation `.pkg` files are encrypted PSN packages,
+   not ZIPs — `pkg2zip` decrypts them.
+2. Set **NoPayStation output dir** in **Settings → Store** (default
+   `$PSP_STATE_DIR/nps`).
+3. Downloading a PSP game writes `PSP/<TITLE_ID>/EBOOT.PBP`; a PS1 Classic
+   writes `PSX/<TITLE_ID>/EBOOT.PBP`. Both then show up in the **Library**
+   (PS1 Classics under **PS1**, PSP games under **Games**) and can be copied to
+   the PSP like any other item.
+4. The TSV lists are cached in the state dir and refreshed on each store scan.
+
+> **DRM note:** NPS content is PSN-DRM'd. To *run* it on the PSP you need the
+> [`npdrm_free`](https://github.com/qwikrazor87/npdrm_free) plugin (ARK and most
+> CFW already ship it). The desktop app only downloads and decrypts; it doesn't
+> strip DRM.
+
 ## Server setup
 
 The catalog + store API is a single-file, stdlib-only HTTP server