Native Minecraft Client Launcher, Profile Engine & Server Browser (#296)

[sivaadityacoder]

Closes #296

What this does

This implements the native Minecraft client launcher, unified profile engine, and server browser requested in #296. The implementation is 100% clean-room, written from scratch against Mojang's launch specifications, and contains no code from HMCL or any other GPL-licensed project to keep AutoPlug fully MIT.

Three major components are introduced:

1. Native Minecraft Launcher

• Mojang version manifest (v2) parsing and OS rule evaluation (Linux, Windows, macOS, architecture flags).
• Multi-threaded parallel asset, library, and native downloader (8 concurrent threads) with SHA-1 hash verification.
• Flexible launch argument builder supporting both legacy single-string arguments and modern rule-based argument arrays with complete parameter substitution (${auth_player_name}, ${version_name}, ${game_directory}, ${classpath}, etc.).
• Offline authentication mode with deterministic UUID v3 generation (vanilla standard), ready for online MSA integration.
• Process runner handling native library extraction, JRE discovery, and non-blocking asynchronous stdout/stderr stream piping via AutoPlug's AsyncInputStream.

2. Unified Profile Engine

• Isolated profile workspaces stored under autoplug/profiles/<name>/.
• Configuration persisted via AutoPlug's existing MyYaml / Dream-YAML architecture (profile.yml).
• Per-profile game version, mod loader support (Vanilla, Fabric, Quilt, Forge), memory allocation limits, custom JVM flags, server auto-connect target, and installed mod tracking.
• Mod version adapter that detects incompatible mods and safely disables them using standard .jar.disabled naming convention.
• Complete CRUD management API (ProfileManager) with directory isolation.

3. Server Browser & Smart Join

• Pure-Java binary NBT decoder and encoder for servers.dat with zero external dependencies, supporting both gzip-compressed and uncompressed formats while preserving unknown NBT tags across round-trips.
• Server List Ping (SLP 1.7+) protocol implementation for live MOTD, player counts, reported server version, and real-time latency measurement.
• Smart join workflow: automatically detects target server version, selects or clones a compatible profile, adapts mods, and launches the client.

CLI & UI Integration

• Console commands integrated under .mc (.mc launch, .mc profile, .mc server, .mc ping).
• UI panels added for Client tab: MinecraftServersPanel and MinecraftProfilesPanel replacing prior placeholder stubs.

Verification & Testing

5 dedicated test suites with 11 automated unit tests passing:

• ProfileTest (CRUD, persistence, isolation)
• MojangManifestTest (manifest v2 parsing & OS rule logic)
• LaunchArgBuilderTest (argument synthesis & placeholder substitution)
• ServersDatTest (NBT serialization round-trip & tag preservation)
• ModVersionAdapterTest (mod disabling & compatibility checking)

mvn test -Dtest=ProfileTest,MojangManifestTest,LaunchArgBuilderTest,ServersDatTest,ModVersionAdapterTest
Tests run: 11, Failures: 0, Errors: 0, Skipped: 0
BUILD SUCCESS

Maintainer Quick Check

.mc profile create default 1.21.1
.mc server add local 127.0.0.1:25565
.mc server ping 127.0.0.1:25565
.mc launch default TestPlayer