feat: add OpenCode/Codex outputs and update changelog (#104)

* Add OpenCode converter coverage and specs

* Add Codex target support and spec docs

* Generate Codex command skills and refresh spec docs

* Add global Codex install path

* fix: harden plugin path loading and codex descriptions

* feat: ensure codex agents block on convert/install

* docs: clarify target branch usage for review

* chore: prep npm package metadata and release notes

* docs: mention opencode and codex in changelog

* docs: update CLI usage and remove stale todos

* feat: install from GitHub with global outputs

src/targets/opencode.ts

@@ -0,0 +1,48 @@
+import path from "path"
+import { copyDir, ensureDir, writeJson, writeText } from "../utils/files"
+import type { OpenCodeBundle } from "../types/opencode"
+
+export async function writeOpenCodeBundle(outputRoot: string, bundle: OpenCodeBundle): Promise<void> {
+  const paths = resolveOpenCodePaths(outputRoot)
+  await ensureDir(paths.root)
+  await writeJson(paths.configPath, bundle.config)
+
+  const agentsDir = paths.agentsDir
+  for (const agent of bundle.agents) {
+    await writeText(path.join(agentsDir, `${agent.name}.md`), agent.content + "\n")
+  }
+
+  if (bundle.plugins.length > 0) {
+    const pluginsDir = paths.pluginsDir
+    for (const plugin of bundle.plugins) {
+      await writeText(path.join(pluginsDir, plugin.name), plugin.content + "\n")
+    }
+  }
+
+  if (bundle.skillDirs.length > 0) {
+    const skillsRoot = paths.skillsDir
+    for (const skill of bundle.skillDirs) {
+      await copyDir(skill.sourceDir, path.join(skillsRoot, skill.name))
+    }
+  }
+}
+
+function resolveOpenCodePaths(outputRoot: string) {
+  if (path.basename(outputRoot) === ".opencode") {
+    return {
+      root: outputRoot,
+      configPath: path.join(outputRoot, "opencode.json"),
+      agentsDir: path.join(outputRoot, "agents"),
+      pluginsDir: path.join(outputRoot, "plugins"),
+      skillsDir: path.join(outputRoot, "skills"),
+    }
+  }
+
+  return {
+    root: outputRoot,
+    configPath: path.join(outputRoot, "opencode.json"),
+    agentsDir: path.join(outputRoot, ".opencode", "agents"),
+    pluginsDir: path.join(outputRoot, ".opencode", "plugins"),
+    skillsDir: path.join(outputRoot, ".opencode", "skills"),
+  }
+}