Adding ht-gitignore-setup to hermes-talaria — Separating Scope Resolution, Template Pinning, and Pre-Write Verification

I added ht-gitignore-setup to hermes-talaria: a skill that creates or improves a .gitignore from upstream templates and repository evidence, targeting either a local directory or a GitHub repository / tree URL. Day-to-day .gitignore work with github/gitignore tends to drift into stacking Global/ OS and editor templates into a shared project file, silently pulling tracked files into the ignore set, or guessing where a tree URL's branch name ends. The skill's SKILL.md pins down scope resolution, upstream SHA pinning, pre-write validation outside the real worktree, and the right way to run git check-ignore. This write-up walks through the design decisions I settled during PR review.