fast-puppy v0.3.0

Rebrands the app as fast-puppy end to end: the CLI command is now fast-puppy; config auto-migrates (non-destructively) from ~/.code_puppy to ~/.fast_puppy; the internal agent id is renamed with a back-compat alias so old sessions still work.

(Versions 0.2.0/0.2.1 were skipped — their PyPI filenames were unavailable from prior deleted uploads.)

Install: pip install fast-puppy then run fast-puppy (or uvx fast-puppy).