fix(frontend): base v2 verified badge on real DB hash matches

[gantoine]

Description
^{Explain the changes or enhancements you are proposing with this pull request.}

Fixes #3806
Fixes #3807

The v2 game-details "Verified ROM" badge was gated on crc_hash being present:

const verified = computed(() => Boolean(currentRom.value?.crc_hash));

A crc_hash (and md5/sha1) is computed for essentially every ROM, so the badge appeared on ROMs that never matched any hash database, e.g. the 7z-compressed Astro Boy GBA ROM in #3806 (which fails to match because of the separate archive-hashing bug #3808, but was still shown as verified).

What changed

• New frontend/src/v2/utils/romVerification.ts — single source of truth for what "verified" means, mirroring the backend's _filter_by_verified (roms_handler.py). A ROM is verified only when a Hasheous signature match flag is set. Exports VERIFICATION_DATABASES, VERIFICATION_KEYS, matchesDatabase(), and isRomVerified().
• GameDetails.vue — the header badge now derives from isRomVerified(currentRom) instead of crc_hash.
• MetadataTab.vue — the per-database chips are now driven by the shared VERIFICATION_DATABASES, so the badge, the chip list, and the backend filter can't drift apart. Fixes the RetroAchievements chip to use ra_match (an actual hash match) instead of ra_id (mere metadata linkage), and adds the previously-missing WHDLoad / PureDOS databases.
• Clarify the badge ([UI/UX] Clarify "verified ROM" status #3807) — the header tooltip now explains what "verified" means (a database hash match via Hasheous / RetroAchievements) via a new rom.verified-rom-hint key added to all 18 locales (translated for en/fr/es/it/pt/de, English placeholder elsewhere). The short "Verified ROM" label is kept as the icon's aria-label.

Note: this is the display/clarity fix. The underlying "7z hashing hashes the archive instead of the ROM" problem is tracked separately in #3808 (backend rahasher.py).

AI assistance disclosure
^{Per CONTRIBUTING.md.}

This PR was written with AI assistance (Claude Code). All changes were reviewed by the author.

Checklist
^{Please check all that apply.}

• 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

Screenshots (if applicable)

N/A

Verification

• romVerification.test.ts: 6 unit tests (no-metadata, hashed-but-unmatched, per-key match, MAME arcade/mess, RA via ra_match, keys-are-flattened) — pass.
• npm run typecheck: clean.
• check_i18n_locales.py + check_i18n_sorted.py: pass.
• trunk fmt + trunk check on all touched files: no issues.

🤖 Generated with Claude Code

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[greptile-apps]

Greptile Summary

This PR bases the verified-ROM UI on actual database hash matches. The main changes are:

• Adds a shared definition of verification databases and match flags.
• Uses that definition for the game header badge and metadata chips.
• Corrects RetroAchievements matching and adds WHDLoad and PureDOS.
• Adds explanatory tooltip text to all supported locales.

Confidence Score: 4/5

The verified badge tooltip needs a keyboard-accessibility fix before merging.

• The frontend verification keys match the backend filter and API schema.
• Missing, partial, and false-valued metadata is handled correctly.
• The tooltip activator cannot receive focus, so keyboard users cannot open it.

frontend/src/v2/components/GameDetails/GameHeader.vue

Important Files Changed

Filename	Overview
frontend/src/v2/utils/romVerification.ts	Adds shared verification helpers whose match keys align with the backend filter and generated API schema.
frontend/src/v2/components/GameDetails/MetadataTab.vue	Moves database chips to the shared definitions and corrects the displayed database match sources.
frontend/src/v2/views/GameDetails.vue	Changes the header badge to require an actual database hash match.
frontend/src/v2/components/GameDetails/GameHeader.vue	Adds the explanatory tooltip, but leaves its parent activator unreachable by keyboard.
frontend/src/v2/utils/romVerification.test.ts	Covers missing and unmatched metadata, every configured flag, MAME variants, and RetroAchievements semantics.

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