fix(plugin): default OCP plugin port to 3478 + env-overridable (v3.16.1) (#95)

* fix(plugin): default OCP plugin port to 3478 + env-overridable; v3.16.1

ocp-plugin/index.js hard-coded http://127.0.0.1:3456 since the plugin
was created. OCP server moved to 3478 default in v3.14+ as part of
the same wave that renamed the launchd label (dev.ocp.proxy). The
plugin never got the memo. Result: `/ocp usage` from OpenClaw bots
(e.g. the home Telegram bot 大内总管) hit the dead port 3456 and
returned "OCP error: fetch failed".

Fix:
- Default PROXY → http://127.0.0.1:3478
- Read OCP_PROXY_URL env (full URL) first
- Else read CLAUDE_PROXY_PORT env (port only, localhost assumed)
- Else fall back to the 3478 default

openclaw.plugin.json bumped (3.12.0 → 3.16.1) and configSchema
default updated. Plugin version now matches OCP version.

Top-level package.json bumped 3.16.0 → 3.16.1. CHANGELOG entry added.

Diagnostic trail: caught 2026-05-12 when home Telegram bot reported
"OCP error: fetch failed" against `/ocp usage`. Mac mini OCP service
was healthy on port 3478; lsof -iTCP:3456 had no listener; plugin
index.js had hardcoded 3456.

No cli.js citation needed: this is OCP-internal plugin code with no
corresponding cli.js operation.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* docs(readme): document OCP_PROXY_URL + CLAUDE_PROXY_PORT plugin reuse (per release_kit 5.5)

---------

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "open-claude-proxy",
-  "version": "3.16.0",
+  "version": "3.16.1",
   "description": "OCP (Open Claude Proxy) — use your Claude Pro/Max subscription as an OpenAI-compatible API for any IDE. Works with Cline, OpenCode, Aider, Continue.dev, OpenClaw, and more.",
   "type": "module",
   "bin": {