fix(scripts): default CLAUDE_PROXY_PORT to 3456 (completes v3.16.2 revert) (#97)

Three places in scripts/ still defaulted to 3478 after v3.16.2's
plugin / manifest / README / plist revert:

  scripts/upgrade.mjs:137
  scripts/doctor.mjs:84
  scripts/doctor.mjs:205

These were the residual cascade source for the port-drift bug originally
caused by the PR #71 dogfood accident on 2026-05-08 (see
~/.cc-rules/memory/learnings/subagent_setup_mjs_prod_host_collision.md
and v3.16.2 CHANGELOG entry).

Every `ocp doctor` / `ocp upgrade` invocation without an explicit
`CLAUDE_PROXY_PORT` in env probed port 3478 — got "OCP not responding"
against a healthy 3456 instance — and on the maintainer's host this
cascaded into wrong baseUrl writes for the OpenClaw `claude-local`
provider, taking out the OpenClaw Telegram agent ("大内总管") on
2026-05-13.

This change is the smallest possible: three string literals
`"3478"` → `"3456"`, aligning unset-env defaults with `server.mjs:126`.
Env-set users are unaffected (env precedence is unchanged).

cli.js: not applicable — this is a scripts/ change, not server.mjs.
ALIGNMENT.md hard-requirements (cli.js citation, blacklist CI,
independent reviewer) target server.mjs; this PR honors the SPOT
spirit by ending the literal-port drift across the codebase.

Bumps to v3.16.3. CHANGELOG entry added.

Co-authored-by: dtzp555 <dtzp555@gmail.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "open-claude-proxy",
-  "version": "3.16.2",
+  "version": "3.16.3",
   "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": {