Blockify

update to MC 26.1.2 with Mojang mappings, bump to 1.3.0-alpha

• Migrate from Yarn to Mojang official mappings (Minecraft 26.1.2 ships unobfuscated)
• Update Loom plugin (net.fabricmc.fabric-loom 1.16-SNAPSHOT), Gradle 9.5.1, Java 25
• Replace InGameHud mixin with Fabric HudElementRegistry
• Move all client logic from BlockifyMain into BlockifyClient (no main entrypoint)
• Migrate API: Minecraft, Component, KeyMapping, GuiGraphicsExtractor, FormattedCharSequence, etc.
• Drop RenderUtil (album art now drawn via GuiGraphicsExtractor.blit)
• Bump fabric-api 0.149.0+26.1.2, midnightlib 1.9.3+26.1-fabric, loader 0.19.2

Bug fixes carried in:

• Fix matrix stack leak when HUD hidden (push without matching pop)
• Guard volume controls against null hudInfo[6] before parseInt
• Fix OAuth callback URL parsing (handled '=' in code, multiple params)
• Fix typo </body? -> </body> in auth success page
• Remove infinite recursion on 'Connection reset' in put/post/addTrack
• Properly terminate Spotify polling thread on InterruptedException