[pfista]

Compatible Xbox v5 multiplayer maps already use the native loader, but the menus only offer the 13 stock maps. This adds discovery of additional v5 caches to both native menu styles, including selection, saved choices, and browser/lobby captions. Stock ordering, names, and previews stay intact.

The multiplayer disk-cache limit increases from 47 MiB to 128 MiB, including direct precaching and the exact boundary. The 22 MiB tag arena is unchanged. Map files must be supplied independently before startup; the change adds no new mode or setting.

The profile keyboard also left Enter in text-entry Done/Start mode after closing, preventing it from activating Create Internet/LAN Game. Synchronize text-entry mode at every keyboard open/close transition and require Enter release before it can activate the underlying menu.

This PR is based directly on upstream main and is independent of the macOS port in #61. It changes shared Windows/Linux/Android engine code and can be reviewed and merged separately. macOS uses the same map support when both PRs are integrated.

Validation:

• Thirteen sanitizer-backed tests pass on this standalone branch, compiling the production scanner, both menu adapters, saved-name handling, cache boundary checks, and profile-keyboard/input lifecycle. The Linux CI job runs these tests.
• Standalone Windows/Linux/Android builds and Linux tests passed.
• A test merge with the unchanged macOS PR Add native ARM64 macOS support using shared Android host services #61 is conflict-free. The combined changes also passed macOS regression checks and Mac app/DMG packaging.
• Before the branch separation, a combined macOS build discovered all 40 locally converted community maps alongside the 13 stock maps. Separate offline Octagon and Weld runs each spawned a player and rendered for about 35 seconds without reported runtime or graphics faults. Weld's declared 58.15 MiB size exceeds the old cache limit. These were macOS integration tests; Windows/Linux/Android multiplayer runtime behavior still needs playtesting.

See the installation and validation limits. Discovery checks headers and capacity; these checks do not establish every map's payload, game-mode behavior, or cross-platform multiplayer compatibility.

[cybersecurity]

Main already handles Halo PC and Custom Edition maps through its own map lists, and #222 already contains its keyboard fix.