v0.2.8 - new metadata cli + api

What's new

• Metadata API — new foehn.parameters(), foehn.stations(), and foehn.inventory() functions to fetch dataset metadata live from the STAC API as Polars DataFrames
• Metadata CLI — new foehn metadata subcommand to inspect parameters, stations, and data inventory from the terminal
  foehn metadata parameters smn
  foehn metadata stations smn
  foehn metadata inventory smn

Breaking changes

• API renames — data_types → time_slice, granularity → frequency, convert() → to_parquet(), key → dataset