Add comprehensive GitHub Copilot instructions for FloatingX development

[Copilot]

This PR adds a comprehensive .github/copilot-instructions.md file that provides GitHub Copilot coding agents with detailed instructions for working effectively in the FloatingX codebase.

What's Included

The instructions provide a complete developer onboarding guide covering:

Build & Test Procedures

• Step-by-step build commands with proper timeout values (15+ minutes for full builds)
• Test execution procedures for unit tests and instrumented tests
• Critical "NEVER CANCEL" warnings for long-running operations
• Library publication workflow for local development

Manual Validation Requirements

• Comprehensive floating window testing scenarios (system, app-level, local scope)
• Specific UI testing procedures for different floating window types
• Permission handling validation (SYSTEM_ALERT_WINDOW)
• Compose integration testing steps
• Edge case testing (immersive mode, RecyclerView, blacklist functionality)

Project Navigation

• Detailed module breakdown (app, floatingx, floatingx_compose)
• Key file locations and their purposes
• API entry points and usage patterns
• Demo application structure and test scenarios

Development Workflow

• Prerequisites (Java 17, Android SDK, network requirements)
• Code quality checks (lint, detekt)
• Debugging commands and troubleshooting guide
• ADB commands for device testing

Key Features

• Imperative tone throughout with clear "Do this", "Never do that" directives
• Explicit timeout values with 50% safety buffers for all build operations
• Real validation scenarios that require actual floating window interaction
• Comprehensive troubleshooting section for common issues
• Network dependency documentation for environments with restricted access

The instructions start with a firm directive to always follow the provided information first, only falling back to additional search when the instructions are incomplete or incorrect.

Example usage pattern documented:

// System floating window (requires permission)
FloatingX.install {
    setContext(context)
    setLayout(R.layout.item_floating)
    setScopeType(FxScopeType.SYSTEM_AUTO)
}.show()

// Local floating window (scoped to Activity)
private val activityFx by createFx {
    setLayout(R.layout.item_floating)
    setEnableLog(true, "activityFx")
    build().toControl(this@MainActivity)
}

This enables GitHub Copilot agents to work efficiently in the FloatingX codebase without extensive exploration or trial-and-error.

Fixes #233.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dl.google.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -Xmx2048m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-all/8fdzzxam9lo77uruaibtsldo0/gradle-8.14.3/lib/gradle-daemon-main-8.14.3.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-all/8fdzzxam9lo77uruaibtsldo0/gradle-8.14.3/lib/agents/gradle-instrumentation-agent-8.14.3.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.14.3 (dns block)
  • Triggering command: curl -I REDACTED (dns block)
• jitpack.io
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -Xmx2048m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-all/8fdzzxam9lo77uruaibtsldo0/gradle-8.14.3/lib/gradle-daemon-main-8.14.3.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-all/8fdzzxam9lo77uruaibtsldo0/gradle-8.14.3/lib/agents/gradle-instrumentation-agent-8.14.3.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.14.3 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.