docs: update server API reference with complete endpoint list

[crayment]

Summary

Updates the server API documentation (/docs/server) to reflect the complete current API surface as of the latest dev branch.

Changes

• Added missing endpoint sections:

  • Global Events (/global/event)
  • Project (/project, /project/current)
  • Path & VCS (/path, /vcs)
  • Instance (/instance/dispose)
  • Provider OAuth (/provider, /provider/auth, /provider/{id}/oauth/*)

• Added missing session endpoints:

  • /session/status - Get status for all sessions
  • /session/{id}/fork - Fork a session at a message
  • /session/{id}/todo - Get todo list for a session

• Added missing message endpoints:

  • /session/{id}/prompt_async - Send message asynchronously (non-blocking)
  • /session/{id}/command - Execute slash commands

• Added experimental tool endpoints:

  • /experimental/tool/ids - List all tool IDs
  • /experimental/tool - List tools with schemas

• Added service status endpoints:

  • /lsp - LSP server status
  • /formatter - Formatter status
  • /mcp - MCP server status

• Added /command endpoint for listing slash commands

• Reorganized documentation into logical groups for better navigation

Generation Method

Documentation was generated from the latest OpenAPI spec using opencode generate command and manually formatted to match the existing docs style.

Context

Fulfills promise made in https://github.com/sst/opencode/issues/3487#issuecomment-3575646390 to update the docs with the latest API spec.