Serve each PKG file as its own FPKGi entry

[gantoine]

Description

The FPKGi feed emitted one entry per rom, keyed by the rom download URL (/roms/{id}/content/...). That endpoint zips multi-file roms, so a PS4 game stored as a folder (base + update + DLC) was served to FPKGi as a single zip and installation failed on the console. Single-.pkg games worked because the same endpoint serves those directly.

The feed now walks each rom's .pkg files and emits one entry per file, keyed by the per-file download URL (/roms/{id}/files/content/...), with that file's own size (FPKGi warns that an inaccurate size breaks downloads).

• Entry names are disambiguated only when a rom holds several packages: "<Game> - Update" / "- DLC" when the file has a scanned category (from a dlc/update/… subfolder), otherwise "<Game> - <file name>". Single-package roms keep their plain name, so existing libraries look unchanged.
• New optional ?content_type= query param (game, dlc, update, patch, demo), so each of FPKGi's CONTENT_URLS slots (games, updates, DLC, …) can point at its own RomM URL. Files without a category folder count as game. Invalid values return 400, matching the existing pkgi endpoints.
• Packages marked missing_from_fs are skipped, so the feed no longer advertises a download that can't resolve.
• title_id is taken from a CUSA/PPSA id in the rom or package file names when present, falling back to the generated ROMM##### id. It is resolved once per rom, so a base game and its updates/DLC stay grouped the way FPKGi searches and sorts content (and the way real PS4 dumps are numbered).
• Drive-by: cover_url is now null when a rom has no cover, instead of a URL pointing at the site root.

Behavior note: a rom with no .pkg files (e.g. a zipped package) is no longer listed. It was listed before, but FPKGi cannot install it.

No frontend regeneration needed: the feed endpoints return a raw Response, so nothing FPKGi-related exists in frontend/src/__generated__/.

Fixes #3962

Checklist

• I've tested the changes locally
• I've updated relevant comments
• I've assigned reviewers for this PR
• I've added unit tests that cover the changes

uv run pytest tests/endpoints/feeds.py → 13 passed. Added test_fpkgi_feed_multi_file_rom (base + update + DLC, a non-pkg file, a missing_from_fs package, shared title id, the content_type filter, and the 400 case) and extended test_fpkgi_feed to assert the per-file name, size and extracted title id.

AI assistance

This PR was written primarily by Claude Code (code, tests and description), reviewed by me before opening.

🤖 Generated with Claude Code

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[greptile-apps]

Greptile Summary

The PR changes the FPKGi feed from one ROM-level archive entry to one entry per PKG file.

• Adds package-category filtering and disambiguated names for multi-package ROMs.
• Uses per-file download URLs and sizes and omits ROMs without PKG files.
• Returns a null cover URL when cover artwork is absent.
• Adds focused feed tests and documents the endpoint behavior.

Confidence Score: 2/5

This PR is not safe to merge until package identifiers are made unique and unavailable PKG records are excluded from the feed.

Multi-package ROMs currently produce entries that FPKGi can collapse under one title ID, while stale file records can produce advertised downloads that fail.

Files Needing Attention: backend/endpoints/feeds.py, backend/tests/endpoints/feeds.py

Prompt To Fix All With AI

Fix the following 2 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 2
backend/endpoints/feeds.py:651
**Duplicate package title identifiers**

When a ROM contains multiple PKG files, every emitted entry derives `title_id` solely from `rom.id`. FPKGi deduplicates aggregate content by this field, causing all but the first base, update, or DLC package for that ROM to disappear and producing incorrect installation status.

### Issue 2 of 2
backend/endpoints/feeds.py:634
**Missing packages remain advertised**

When a PKG has been removed from storage but its record is marked `missing_from_fs`, this extension-only filter still adds it to the feed. FPKGi displays the unavailable package, then installation fails because the generated download URL references a file that no longer exists.

_{Reviews (1): Last reviewed commit: "List each PKG file as its own FPKGi entr..." | Re-trigger Greptile}