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/core/test/plugin/fixtures/models-dev.json

@@ -0,0 +1,14 @@
+{
+  "acme": {
+    "id": "acme",
+    "name": "Acme",
+    "env": ["ACME_API_KEY"],
+    "models": {}
+  },
+  "local": {
+    "id": "local",
+    "name": "Local",
+    "env": [],
+    "models": {}
+  }
+}