models list: stop truncating ids

[andredezzy]

Problem

models list pads the id column with padding(toLength: 26, …), and Swift's
padding(toLength:) truncates when the string is longer than the target. Any
id past 26 characters is printed cut off, and a cut id cannot be pasted into
parrot models download.

Reproducible with any longer id. Adding a 33-character one to the registry:

  whisper-large-v3-turbo-com   632 MB  [multi]    Whisper Large v3 Turbo (compressed)

The command's whole purpose is to give the user a value to copy, so silently
corrupting it defeats the feature.

Fix

Size the column to the longest id in the registry instead of a fixed 26. Output
with the same registry:

★ whisper-base.en                     145 MB  [en]       Whisper Base (English)
  whisper-large-v3-turbo             1620 MB  [multi]    Whisper Large v3 Turbo
  whisper-large-v3-turbo-compressed   632 MB  [multi]    Whisper Large v3 Turbo (compressed)
  whisper-small.en                    488 MB  [en]       Whisper Small (English)

Current ids all fit in 26 characters, so nothing changes for them today — this
only stops the next longer id from being mangled.

Built locally with swift build -c release (no PR CI in this repo); clean, no
warnings.