feat: split company metadata into publishers and developers

[gantoine]

Description

Metadata providers (ScreenScraper, RetroAchievements, LaunchBox, Flashpoint, gamelist, IGDB) distinguish the publisher from the developer of a game, but RomM amalgamates both into a single companies list at ingestion, so the distinction is unrecoverable (which breaks round-tripping to tools like LaunchBox/Pegasus where it matters to collectors).

This threads two new refined fields, publishers and developers, end to end. companies is kept unchanged as the merged union, so nothing existing breaks; the split is purely additive.

Backend

• Handlers now emit publishers/developers alongside the unchanged companies list (ss, ra, launchbox, flashpoint, gamelist, igdb, hasheous). IGDB requests the involved_companies.developer/.publisher flags to split by role.
• Migration 0102 adds generated_publishers/generated_developers STORED columns on roms, projects them through the roms_metadata view (appended, so nothing shifts), mirrors them into roms_facets, and adds publisher/developer virtual-collection types. All triggers/functions rebuilt for MariaDB/MySQL + PostgreSQL; upgrade/downgrade round-trips and live trigger-sync verified.
• Filters, facets, endpoints, smart collections, and the gamelist/Pegasus exporters all carry the new fields. The exporters now prefer the explicit split and fall back to the old companies[0]/[1] heuristic for ROMs scanned before the split.

Frontend (v2)

• Shared filter store + API service, gallery filter drawer, URL persistence, game-detail display (shows Developers/Publishers, falls back to the merged Companies), edit dialog, smart-collection criteria, and a publisher/developer "group virtual collections by" option.
• Also relabels the confusing company → "Developer" group-by option to "Company" now that a proper Developer option exists.
• 4 new i18n keys added to all 18 locales (non-English get English placeholders pending community translation).

Notes

• Existing libraries only populate companies until ROMs are re-scanned (the split reads raw provider blobs that predate the new keys). companies stays fully populated meanwhile.
• Scoped new UI to v2 per the repo's "v1 is frozen" rule; v1 keeps companies as-is.

AI-assistance disclosure

This PR was implemented with substantial assistance from Claude (Claude Code). AI was used to map the companies data flow, write the migration and the handler/schema/filter/frontend changes, and author the tests. All changes were reviewed and verified locally by the author.

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

Testing

• Backend: alembic upgrade head/downgrade -1 round-trip on MariaDB; 906 passed / 2 skipped across handler/database/metadata/utils/endpoints (incl. new generated-column, facets, and exporter tests).
• Frontend: vue-tsc typecheck clean, vitest green (incl. new smart-collection criteria tests), npm run generate regenerated types, i18n parity + sorted checks pass.
• Trunk clean on all changed files.

[Copilot]

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[greptile-apps]

Greptile Summary

Adds distinct publisher and developer metadata throughout the application while preserving the existing merged companies field.

• Extends metadata-provider mappings, generated database metadata, facets, filters, smart collections, and virtual collections.
• Adds publisher/developer editing, filtering, URL persistence, grouping, and display support to the v2 frontend.
• Updates gamelist and Pegasus exporters to prefer explicit role metadata while retaining legacy company fallbacks.
• Adds backend and frontend tests for generated metadata, facets, exporters, and smart-collection criteria.

Confidence Score: 5/5

The PR appears safe to merge, with the publisher/developer split consistently threaded through persistence, APIs, filtering, exports, and the v2 interface.

The new role fields preserve the existing companies contract, use the established metadata precedence and JSON-filter paths, rebuild dependent database synchronization structures for both supported dialect families, and retain explicit compatibility fallbacks for metadata created before this change.

Important Files Changed

Filename	Overview
backend/alembic/versions/0102_publisher_developer_split.py	Adds dialect-aware generated columns, metadata-view projections, facet synchronization, and publisher/developer virtual-collection memberships with a coordinated downgrade.
backend/handler/metadata/igdb_handler.py	Requests and separates IGDB involved-company publisher and developer roles while retaining the existing companies output.
backend/handler/database/roms_handler.py	Extends ROM filtering, facet extraction, and metadata-join selection with publisher and developer fields using the existing JSON-filter semantics.
backend/handler/database/collections_handler.py	Threads publisher and developer criteria, including legacy single-value forms, into smart-collection evaluation.
backend/endpoints/roms/init.py	Exposes publisher/developer filters and logic operators and correctly treats them as scoped queries for sidecar caching.
backend/utils/gamelist_exporter.py	Exports explicit developer and publisher metadata first, falling back to the established legacy company positions.
backend/utils/pegasus_exporter.py	Applies the same explicit-role preference and legacy company fallback to Pegasus metadata output.
frontend/src/stores/galleryFilter.ts	Adds complete publisher/developer filter state, logic, setters, active-filter detection, and reset behavior.
frontend/src/v2/composables/useGalleryFilterUrl/index.ts	Persists and restores publisher/developer selections and logic operators through gallery URLs.
frontend/src/v2/utils/smartCollectionCriteria.ts	Includes publisher and developer filters in smart-collection criteria construction and human-readable summaries.
frontend/src/v2/views/GameDetails.vue	Displays split role metadata when available and preserves the merged-companies fallback for libraries not yet rescanned.

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