Add linux_arm64 builds for Ebitengine and Bevy

Batocera and the ES-family distributions run on ARM as much as on
x86_64 — Raspberry Pi, Odroid, the retro handhelds — and a linux_x64
binary installs there but will not start. There was no Linux ARM asset
kind at all: KINDS had linux_x86 and linux_x64 and mac_arm64, but
nothing for 64-bit ARM Linux.

Registering the kind is deliberately separate from producing it: a
platform service only includes BuildLinuxArm64 once its pipeline builds
the artifact, otherwise /api/builds would report it missing for every
release. Hence Ebitengine and Bevy only. Godot needs a Linux arm64
export preset in each game repo first; LÖVE fuses an upstream AppImage
that ships x86_64 only; TIC-80's export command has no ARM target.

Ebitengine needs cgo on Linux, so binary_build gained a cross-compiler
argument — and unsets CC for native targets, otherwise a build after
the ARM one silently picks up the cross gcc.

Verified by cross-compiling both demos in the rebuilt images: each
produced a genuine AArch64 ELF (e_machine 183), not a silent fallback.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/frontend/src/i18n/locales/en.ts

@@ -160,6 +160,7 @@ export default {
       win_x64: 'Windows (64-bit)',
       linux_x86: 'Linux (32-bit)',
       linux_x64: 'Linux (64-bit)',
+      linux_arm64: 'Linux (ARM 64-bit)',
       mac_x64: 'macOS (Intel)',
       mac_arm64: 'macOS (Apple Silicon)',
       mac_universal: 'macOS',

apps/frontend/src/i18n/locales/hu.ts

@@ -160,6 +160,7 @@ export default {
       win_x64: 'Windows (64 bit)',
       linux_x86: 'Linux (32 bit)',
       linux_x64: 'Linux (64 bit)',
+      linux_arm64: 'Linux (ARM 64 bit)',
       mac_x64: 'macOS (Intel)',
       mac_arm64: 'macOS (Apple Silicon)',
       mac_universal: 'macOS',

apps/frontend/src/page/builds/BuildsIndexPage.vue

@@ -120,6 +120,7 @@ const columnGroups = [
     color: 'group-amber',
     kinds: [
       { kind: 'linux_x64', sub: '64 bit' },
+      { kind: 'linux_arm64', sub: 'ARM 64 bit' },
     ],
   },
   {

apps/frontend/src/page/catalog/CatalogShowPage.vue

@@ -314,7 +314,7 @@ const downloadUrl = (path: string) =>
 // az asset-táblázat sorai és sorrendjük; a html nem letöltés, azt a Play gomb viszi
 const TABLE_KIND_ORDER = [
   'cartridge', 'source', 'docs',
-  'win_x64', 'win_x86', 'linux_x64', 'linux_x86',
+  'win_x64', 'win_x86', 'linux_x64', 'linux_arm64', 'linux_x86',
   'mac_universal', 'mac_arm64', 'mac_x64',
 ]