UEVR: address the second review; recheck on the Frame

frame_inject.py declares every Win32 signature, checks each result, frees
its remote buffers and closes handles. Uninstall only accepts our folder and
UEVR's own per-game settings folders, and keeps the receipt if anything can't
be removed. The injector's reply is parsed defensively. Rechecked on a real
Frame: install, three cold starts injected (33-35 s), clean uninstall.

Part of #26.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/mods.md

@@ -26,7 +26,7 @@ means an upstream source describes it; “inferred” means it still needs a tes
 | Game / build | Mod or content | Evidence and support status | Next check |
 |---|---|---|---|
 | Half-Life 2: VR Mod – Episode One, Steam 2177750, build 25413453 | Official Steam community mod, shared base depot 658920 build 25413418 | **Verified: startup only.** Already installed; launched through Proton ARM64. The stereo headset capture showed its first-time setup, and SteamVR loaded `bindings_frame.json`. Gameplay, controller interaction, fresh installation and removal are unverified. | Complete first-time setup and play a level before offering a tested install shortcut. |
-| Gravitas, Steam 1067310, Windows, Unreal Engine 4 | UEVR 1.05, from Frame Control | **Verified 2026-09-29: installs, injects, SteamVR receives frames, removes cleanly.** Nine cold **Play in VR** runs (33–35 s each), then the full cycle again from the app's UI, all loaded `UEVRBackend.dll` into the game, with UEVR logging `Hooked DirectX 11` and `Requested runtime: openvr_api.dll`. SteamVR's compositor counted frame submits for `steam.app.1067310`. Remove restored the prefix to its pre-install file listing. **Not seen:** the stereo image, head tracking and controls (headset unworn). | Wear the headset: check the image, tracking, UEVR's in-headset menu and controller input. |
+| Gravitas, Steam 1067310, Windows, Unreal Engine 4 | UEVR 1.05, from Frame Control | **Verified 2026-09-29: installs, injects, SteamVR receives frames, removes cleanly.** Twelve cold **Play in VR** runs (33–35 s each), and the full cycle from the app's UI, all loaded `UEVRBackend.dll` into the game, with UEVR logging `Hooked DirectX 11` and `Requested runtime: openvr_api.dll`. SteamVR's compositor counted frame submits for `steam.app.1067310`. Remove restored the prefix to its pre-install file listing. **Not seen:** the stereo image, head tracking and controls (headset unworn). | Wear the headset: check the image, tracking, UEVR's in-headset menu and controller input. |
 | Beat Saber, Steam 620980, Windows / Proton | Basic custom songs; later SongCore and version-matched mods | **Verified: absent from the 868-game library returned by this Frame.** Store metadata lists Windows, not Linux. **Documented:** the PC game reads basic maps from `Beat Saber_Data/CustomLevels` without a mod manager. Playback on Frame is unverified. | An already-owned, legitimately installed copy is required. Do not buy it as part of this task. |
 | Beat Saber, claimed native ARM64 build | Custom songs / native mods | **Inferred: unverified.** The research mentions this build but supplies no verified official distributable or tested layout. CPU architecture alone does not identify Android versus Linux, the game version or the mod ABI. | Establish official provenance, ownership, binary type and version before touching files. Do not apply Quest patches to an unidentified build. |
 | Beat Saber, Alex's Quest 2 copy | Custom songs / Android mods | **Documented: owner-reported copy on Quest 2.** Not reachable on 2026-09-29 (no device on `adb` from the Mac). No APK, version or installed mods inspected; no Frame playback verified. A Quest copy is a Meta store purchase; copying it to another headset would need its entitlement check to pass there, which this work won't work around. This does not establish ownership of the Steam build. | When the Quest is available, inspect the owned copy's version and supported transfer path, then test Lepton/OpenXR compatibility without bypassing entitlement checks. |
@@ -95,7 +95,7 @@ Why not UEVR's own injector (verified 2026-09-29):
   cross-process window message; a window that isn't answering would block its
   UI thread (inferred from the frontend's source, not proven). Without a
   `HOME` it also died in .NET at startup.
-- Frame Control's own script injected in 9 of 9 cold starts, in 33–35 s.
+- Frame Control's own script injected in 12 of 12 cold starts through the API, in 33–35 s, and again from the UI.
 - UEVR's DirectX 12 probing logs errors before it settles on DirectX 11 for
   Gravitas, and some of its Unreal engine scans fail on this older UE4 game.
   Neither stopped the injection.