* docs: add OpenChamber feature docs and translations
Add 30 new docs pages covering OpenChamber-specific workflows and setup:
OpenCode server, providers/models/agents, MCP, skills, commands & snippets,
usage, projects, context, notes/todos/plans, scheduled tasks, project actions,
preview, worktrees, multi-run, git & GitHub, magic prompts, git identities,
mobile/PWA, security, notifications, voice, project icons, remote instances,
desktop browser, updates, and three troubleshooting pages.
Rebuild sidebar into eight task-oriented sections and translate every new
page into all six supported locales (uk, zh-cn, es, pt-br, ko, pl).
* docs: surface new sections on homepage and cross-link tunnels
Add an Explore block to the docs homepage (all seven locales) linking to
the new section anchors, and cross-link the Tunnels page to Security and
PWA & Mobile.