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/containers/base/Dockerfile

@@ -0,0 +1,18 @@
+FROM ubuntu:24.04
+
+ARG DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends \
+    build-essential \
+    ca-certificates \
+    curl \
+    git \
+    jq \
+    openssh-client \
+    pkg-config \
+    python3 \
+    unzip \
+    xz-utils \
+    zip \
+  && rm -rf /var/lib/apt/lists/*