chore(skills/mcp-oauth-remote-gateway): move to optional-skills + modernize
- Move skills/mcp/ -> optional-skills/mcp/ (niche remote-deployment
workflow; bundled tier is for daily-driver skills)
- Frontmatter: description 421 -> 57 chars, add platforms gating
[linux, macos] (bash pipelines + gateway hosts), credit Ben Barclay
first in author
- Document the built-in flow's own escape hatches (paste-back prompt,
ssh -N -L port-forward) as cheap first fallbacks before manual
token surgery; scope the skill to no-TTY messaging-gateway contexts
- Frame execution through the terminal / execute_code tools
- Tests: tests/skills/test_mcp_oauth_remote_gateway_skill.py covers
all four diagnostic branches, atomic --write persistence, 0600
perms, httpx UA on the wire, no-secrets-in-stdout, and frontmatter
invariants (9 passing)
- Regen auto-gen docs page + one-line catalog row + sidebar entry
(scoped; unrelated generator drift reverted)
5f171e36ab