fix: improve plugin system robustness — agent/command resolution, async errors, hook timing, two-phase init (#18280)

Co-authored-by: Aiden Cline <63023139+rekram1-node@users.noreply.github.com>

packages/opencode/test/plugin/auth-override.test.ts

@@ -54,3 +54,19 @@ describe("plugin.auth-override", () => {
     expect(plainMethods[ProviderID.make("github-copilot")][0].label).not.toBe("Test Override Auth")
   }, 30000) // Increased timeout for plugin installation
 })
+
+const file = path.join(import.meta.dir, "../../src/plugin/index.ts")
+
+describe("plugin.config-hook-error-isolation", () => {
+  test("config hooks are individually error-isolated in the layer factory", async () => {
+    const src = await Bun.file(file).text()
+
+    // The config hook try/catch lives in the InstanceState factory (layer definition),
+    // not in init() which now just delegates to the Effect service.
+    expect(src).toContain("plugin config hook failed")
+
+    const pattern =
+      /for\s*\(const hook of hooks\)\s*\{[\s\S]*?try\s*\{[\s\S]*?\.config\?\.\([\s\S]*?\}\s*catch\s*\(err\)\s*\{[\s\S]*?plugin config hook failed[\s\S]*?\}/
+    expect(pattern.test(src)).toBe(true)
+  })
+})