Adopt the orphaned mise installs into Nix

Adopt the orphaned mise installs into Nix ffmpeg, vips, postgresql and cargo-deny were installed under mise but declared nowhere - not in the global config, not in any of the eight project mise.toml files. They were residue from before the migration, roughly 1.1 GB of it. postgresql_17 rather than the default postgresql: nixpkgs ships 18.6, mise had 17.11, and a major version cannot read an existing v17 data directory without pg_upgrade. postgresql_17 is exactly 17.11, so nothing has to migrate. No local data directories were found either way. pnpm and rust were also orphaned in mise but were already declared here, so they need nothing. Brings the package set to 64 plus the two home-manager injects.