TyperAdapter.command property undocumented in typer-adapter.md

[codeforester]

Problem

docs/typer-adapter.md documents TyperAdapter.attach() and attach_typer() but never mentions that TyperAdapter.command exposes the cached Click command tree directly. This property is set in TyperAdapter.__init__ (verified in typer.py) and gives consumers access to the Click command without calling attach() first.

Consumers who build test harnesses, routing tables, or multi-level composition need to access adapter.command without triggering the full attach() lifecycle. Without documentation, they must read the source code to discover this.

Fix

Add one sentence to docs/typer-adapter.md in the section that introduces TyperAdapter:

The cached Click command is available as adapter.command when access is needed before or without calling attach() — for example, in test assertions or composition with another Click group.

Also add a one-line docstring to the command property in typer.py if it is currently missing one.