Add connect() client mode and Japanese README

[Moge800]

Summary

One package now covers both "bundle and run the server" and "just be a client", over the same PLCClient:

• connect(base_url, token=None) — talk to a gomc-rest server already running elsewhere (another machine, a shared instance, or one started with server_mode=True) without spawning the bundled binary. Returns a PLCClient and supports the context-manager protocol.
• Existing launch() (bundle + auto-start, private by default or exposed via server_mode=True) is unchanged.

This reuses gomc-rest-client — no protocol or HTTP-client reimplementation, so there is no second source of truth to keep in sync.

import gomc_rest

# bundled server, private (loopback)
with gomc_rest.launch(plc_host="192.168.0.1") as plc:
    plc.read("D100", 3)

# client only: connect to an existing server
with gomc_rest.connect("http://192.168.0.1:8080", token="...") as plc:
    plc.read("D100", 3)

Changes

• src/gomc_rest/__init__.py: add connect(), export it, update module docstring.
• README.md / README_JP.md: document the client mode; add a Japanese README with an English/日本語 cross-link.

Notes

• No dependency or behavior change to launch().
• connect() is a thin wrapper over PLCClient(base_url, token=...).

🤖 Generated with Claude Code

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