feat: add "Open in Flashpoint" game action

[gantoine]

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

Adds a v2 game action, Open in Flashpoint, that launches a title in the locally installed Flashpoint launcher.

When a ROM has a flashpoint_id (its Flashpoint game UUID, already present on the ROM schema), the action hands that UUID to the OS flashpoint://<uuid> protocol handler. The launch uses a synthesized, self-removing <a> element rather than window.open, so no blank tab is left behind when the handler takes over. The button/menu item only appears when the ROM actually has a flashpoint_id.

Changes:

• useGameActions composable: new canOpenInFlashpoint gate and openInFlashpoint() handler.
• GameActionBtn.vue: new "flashpoint" action + preset (mdi-rocket-launch-outline).
• GameActions.vue and GameActionsList.vue: render the action when available.
• Added the rom.open-in-flashpoint key to all 18 locales (English value; translators can localize later).

No backend changes are needed; flashpoint_id is already exposed on the ROM schema.

This is a frontend-v2-only feature, so it is gated behind the v2 UI.

AI assistance disclosure: This PR was implemented with AI assistance (Claude Code). The feature was reimplemented against the latest master, and all code and locale entries were AI-generated and human-reviewed.

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)

🤖 Generated with Claude Code

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[greptile-apps]

Greptile Summary

This PR adds an Open in Flashpoint action to the v2 interface. The main changes are:

• Adds a flashpoint:// launch handler and availability gate.
• Adds the action to the game action bar and overflow menu.
• Adds the action label to all supported locales.

Confidence Score: 4/5

The launch URI needs input validation before merging.

• The UI wiring and reactive ROM access follow existing action patterns.
• The backend permits non-UUID values, while the new launch path assumes every non-empty value is a valid identifier.
• URI delimiters in a stored value can make Flashpoint receive the wrong game ID.

frontend/src/v2/composables/useGameActions/index.ts

Important Files Changed

Filename	Overview
frontend/src/v2/composables/useGameActions/index.ts	Adds the Flashpoint availability check and protocol launch handler; arbitrary stored IDs can produce malformed launch URIs.
frontend/src/v2/components/GameActions/GameActionBtn.vue	Adds the Flashpoint action type, icon, label, and click callback.
frontend/src/v2/components/GameActions/GameActions.vue	Conditionally adds the labeled Flashpoint button to the main action group.
frontend/src/v2/components/GameActions/GameActionsList.vue	Conditionally adds the Flashpoint action to the overflow menu.
frontend/src/locales/*/rom.json	Adds the Open in Flashpoint label to all 18 locale catalogs.

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
frontend/src/v2/composables/useGameActions/index.ts:292
**Unvalidated ID Changes Launch URI**

The ROM update API can store any non-empty string in `flashpoint_id`, but this line inserts that value directly into the URI. A stored value such as `game#variant` or `game?variant` is parsed as a fragment or query, so Flashpoint receives the wrong identifier and the enabled action silently fails. Validate the value as a UUID before exposing and launching this action.

_{Reviews (1): Last reviewed commit: 23ff801 | Re-trigger Greptile}