feat: OpenCode v1.1.1 permission system compatibility (#489)

* feat: add OpenCode v1.1.1 version detection and permission compatibility utilities

- Add opencode-version.ts: Detect installed OpenCode version and support API
- Add permission-compat.ts: Compatibility layer for permission system migration
- Add comprehensive tests (418 lines total)
- Export new utilities from shared/index.ts

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

* fix: update agent permission configs for OpenCode v1.1.1 compatibility

- Fix document-writer: change invalid 'permission: { background_task: deny }' to 'tools: { background_task: false }'
- Fix explore: split 'permission' and 'tools' config, move tool-level denials to 'tools' key
- Fix oracle: split 'permission' and 'tools' config, move tool-level denials to 'tools' key
- Align all agents with v1.1.1 permission system structure

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

src/shared/opencode-version.ts

@@ -0,0 +1,72 @@
+import { execSync } from "child_process"
+
+export const PERMISSION_BREAKING_VERSION = "1.1.1"
+
+const NOT_CACHED = Symbol("NOT_CACHED")
+let cachedVersion: string | null | typeof NOT_CACHED = NOT_CACHED
+
+export function parseVersion(version: string): number[] {
+  const cleaned = version.replace(/^v/, "").split("-")[0]
+  return cleaned.split(".").map((n) => parseInt(n, 10) || 0)
+}
+
+export function compareVersions(a: string, b: string): -1 | 0 | 1 {
+  const partsA = parseVersion(a)
+  const partsB = parseVersion(b)
+  const maxLen = Math.max(partsA.length, partsB.length)
+
+  for (let i = 0; i < maxLen; i++) {
+    const numA = partsA[i] ?? 0
+    const numB = partsB[i] ?? 0
+    if (numA < numB) return -1
+    if (numA > numB) return 1
+  }
+  return 0
+}
+
+export function isVersionGte(a: string, b: string): boolean {
+  return compareVersions(a, b) >= 0
+}
+
+export function isVersionLt(a: string, b: string): boolean {
+  return compareVersions(a, b) < 0
+}
+
+export function getOpenCodeVersion(): string | null {
+  if (cachedVersion !== NOT_CACHED) {
+    return cachedVersion
+  }
+
+  try {
+    const result = execSync("opencode --version", {
+      encoding: "utf-8",
+      timeout: 5000,
+      stdio: ["pipe", "pipe", "pipe"],
+    }).trim()
+
+    const versionMatch = result.match(/(\d+\.\d+\.\d+(?:-[\w.]+)?)/)
+    cachedVersion = versionMatch?.[1] ?? null
+    return cachedVersion
+  } catch {
+    cachedVersion = null
+    return null
+  }
+}
+
+export function supportsNewPermissionSystem(): boolean {
+  const version = getOpenCodeVersion()
+  if (!version) return true
+  return isVersionGte(version, PERMISSION_BREAKING_VERSION)
+}
+
+export function usesLegacyToolsSystem(): boolean {
+  return !supportsNewPermissionSystem()
+}
+
+export function resetVersionCache(): void {
+  cachedVersion = NOT_CACHED
+}
+
+export function setVersionCache(version: string | null): void {
+  cachedVersion = version
+}