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/opencode/test/util/data-url.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, test } from "bun:test"
+import { decodeDataUrl } from "../../src/util/data-url"
+
+describe("decodeDataUrl", () => {
+  test("decodes base64 data URLs", () => {
+    const body = '{\n  "ok": true\n}\n'
+    const url = `data:text/plain;base64,${Buffer.from(body).toString("base64")}`
+    expect(decodeDataUrl(url)).toBe(body)
+  })
+
+  test("decodes plain data URLs", () => {
+    expect(decodeDataUrl("data:text/plain,hello%20world")).toBe("hello world")
+  })
+})