📎 Execute Biome command on the working directory by default

[Conaclos]

Description

See #2240 for more context.

For now, The main Biome commands require passing at least one file (possibly a directory).
For instance, to format all files in the working directory, a user has to run biome format ./.

Running a Biome command on the working directory is really common.
We should allow to omit the path and default to the working directory.
Thus, biome <format|lint|check> should be equivalent to biome <format|lint|check> ./.