0.3.3 — Fix overlay never showing on MC 26.1

Bug fix

In 0.3.2 the overlay UI was supposed to light up on MC 26.1.x, but the runtime probe in MultiViewMod.onInitializeClient was looking up net.minecraft.client.gui.GuiGraphics, which doesn't exist on 26.1 (Mojang renamed the class to GuiGraphicsExtractor). The probe failed, the UI was skipped, and the chat-only fallback kicked in — exactly the state we were trying to leave behind.

0.3.3 drops the rendering-class probe and instead loads fr.zeffut.multiview.ui.MergeUi directly via reflection. The class is naturally version-gated by its imports (1.21.x build imports GuiGraphics, 26.1+ build imports GuiGraphicsExtractor), so a successful Class.forName is sufficient to know that the UI can render on the current runtime.

Verified by launching MC 26.1.1 + Fabric Loader 0.19.2 + Flashback 0.40.0 with the produced jar: the log now reads [MultiView] MergeUi registered (Phase 5 — per-replay checkboxes, MC 26.1+ variant) instead of UI disabled on this MC version (ClassNotFoundException).

What this means

If you tried 0.3.2 on MC 26.1 and the merge button never appeared in Select Replay, this is the version that fixes it. No new bugs, no behavior change on 1.21.x.