v0.1.0: feat: implement Copy Code Location plugin for JetBrains IDEs

Add IntelliJ Platform plugin that allows users to copy file path with line
numbers from the editor context menu.

Features:
- Copy Code Location (Relative): copies path relative to project root
- Copy Code Location (Absolute): copies absolute file path
- Supports both cursor position (single line) and selection (line range)
- Output format: path:line or path:start-end

Technical details:
- Built with org.jetbrains.intellij.platform plugin 2.2.1
- Compatible with IntelliJ Platform 2024.3.5+
- Uses ActionUpdateThread.BGT for proper EDT handling
- Includes Gradle wrapper 8.6 for consistent builds

Closes: initial plugin implementation