feat(models): port model discovery to match opencode_local adapter

Replace static hardcoded fallback list with the same robust approach used
by the opencode_local adapter: runChildProcess + ensurePathInEnv, HOME fix
via os.userInfo(), 60s TTL cache, returns [] on failure instead of a stale
list. Also updates CLAUDE.md and README.md with missing fields/features.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "paperclip-adapter-opencode-k8s",
-  "version": "0.1.33",
+  "version": "0.1.34",
   "description": "Paperclip adapter plugin that runs OpenCode agents as Kubernetes Jobs",
   "license": "MIT",
   "type": "module",