chore: spin off Pokémon ROM-hack material to standalone repo

The Pokémon catalog + pipeline are moved out of this infra repo. The catalog
notes now live in the self-hosted Obsidian vault (Pokémon ROM Hacks/); the
acquisition/patching scripts live in their own repo at Documents\pokemon.
homelabstack stays focused on the homelab.

- rm pokemon-romhack-vault/ (75 hack notes + Index/Types/README/Platforms)
- rm scripts/{build-romhack-vault,romhack-import,romhack-fetch,romhack-apply}.py
- rm pokemon-romhacks-wanted.md
- .gitignore: drop the now-dead pokemon/ drop-folder rule
- .claude/skills/vault/SKILL.md: condense the Pokemon-vault subtree to a one-line pointer

RomM stack (stacks/roms) and the general igir library scripts stay.

.gitignore

@@ -11,9 +11,5 @@ Thumbs.db
 *.tmp
 *.log
 
-# ROM-hack drop folder — large binaries processed into the valhalla library by
-# scripts/romhack-import.py; never commit the ROMs themselves.
-pokemon/
-
 # Personal, per-machine Claude Code overrides (not team config)
 .claude/settings.local.json