Add "Installing Python and pip" (EN/JP) A page for users without a working Python: installing Python and pip on Windows, macOS and Linux, then pointing on to the platform pages. Its troubleshooting section covers the macOS problem users keep hitting: the python.org installer leaves Python without root certificates, so pip works (it ships its own bundle) but the Plugin Installer, PubChem lookups and other online features fail with CERTIFICATE_VERIFY_FAILED until Install Certificates.command is run. It also covers proxies, "pip not found", externally-managed-environment, and picking a Python version. Linked from Home, both Troubleshooting pages, and the opening of every platform installation page; the macOS pages also mention the certificate step directly. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
docs: add Japanese installation pages for Windows, macOS and Linux Docker was the only installation page with a JP counterpart, so Japanese readers hit English for the three platform installs the wiki actually recommends. Translate all three, list them on Home, and repoint the existing JP pages (and Docker-JP) at the JP versions. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>