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
- System prompt injection for routing
- V1 requirements: C4 docs, ADR, AGENTS.md, debug-log.md
- Design documents in docs/

packages/storybook/.storybook/mocks/app/components/dialog-select-model-unpaid.tsx

@@ -0,0 +1,3 @@
+export function DialogSelectModelUnpaid() {
+  return <div data-component="dialog-select-model-unpaid">Select model</div>
+}