feat(aircoding): AirCoding V2 baseline — deterministic multi-agent architecture

Forked from OpenCode v1.17.4 with multi-agent system:
- 5 agents: aircoding, scheduler, worker, architect, reviewer
- Deterministic DAG scheduling engine (coordinator_tick)
- Tool whitelists as hard enforcement
- AirCoding validation plugin
- V1 requirements: C4 docs, ADR, AGENTS.md, debug-log.md
- Design documents in docs/

packages/desktop/resources/linux/opencode-desktop.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Name=OpenCode
+Exec=/opt/OpenCode/ai.opencode.desktop %U
+Terminal=false
+Type=Application
+Icon=ai.opencode.desktop
+StartupWMClass=ai.opencode.desktop
+NoDisplay=true
+Comment=Open source AI coding agent
+Categories=Development;