[Flapjacck]

Summary

Full refactor away from the original Fabric template's placeholder package and class names. Moves everything into a single src/main source set, reorganises the Java tree by concern, and renames classes to match the mod ID.

Related issues

None

Changes

• Replaced com.example.itemtweaks package with com.flapjacck.swing across all Java files and config JSON
• Merged ItemTweaks + ItemTweaksClient into a single Swing.java entrypoint
• Renamed ItemTweaksConfig → SwingConfig (moved to config/ subpackage)
• Moved SwingCommandHandler to command/ and SwingSettingsScreen to screen/
• Collapsed all mixins into mixin/ under the main source set; merged swing.client.mixins.json into swing.mixins.json
• Removed splitEnvironmentSourceSets() — mod is client-only, single source set is cleaner
• Updated loom mods block from "itemtweaks" to "swing" to match mod ID
• Renamed mixin method prefixes from itemtweaks$ to swing$
• Moved assets/itemtweaks/ → assets/swing/ to match the mod ID Fabric expects
• Stripped maven-publish boilerplate and dead template comments from build.gradle
• Updated gradle.properties group to com.flapjacck.swing
• Version bump to v1.5.0