Remove vendored throughput-forecast files; skill now installed globally

[rhyslutsky]

Summary

• Removes everything the throughput-forecast GitHub-Projects port (Port throughput-forecast skill to GitHub Projects v2 (Project #50) #653, throughput-forecast: breakdown by parent, exclude parent-container issues, daily Voice Selection report #664) vendored into this repo: .claude/scripts/{gh_fetch.py,forecast.py,forecast-html.py}, .claude/skills/throughput-forecast/{SKILL.md,config.yaml}, and the .claude/settings.json that existed solely for those scripts' Bash allowlist.
• create-ticket (create-ticket: auto-add issues to Project #50 and link sub-issue parents #654/create-ticket: auto-add issues to Project #50 and link sub-issue parents #656) is untouched — separate concern, explicitly out of scope.
• No merged history reverted — this is a normal forward delete commit, safe regardless of other branches built on feature/voice-selection since.

Why

Per review feedback on #655/#666: rather than relocating gh_fetch.py into dq-documentation while still keeping project-specific copies vendored here, the whole skill (gather script + engine + config + docs) is now installed globally at ~/.claude/skills/github-throughput-forecast/ — available for any GitHub Projects v2 board, without committing anything into any one app's repo. PR #665 (the parent-breakdown follow-up) was closed unmerged rather than revised — its fixes were carried over into the global install directly.

Ticket

Closes #666 — same non-default-branch caveat as prior PRs in this thread: will manually close after merge since closes #N won't auto-fire against feature/voice-selection.

Type of Change

• New feature
• Bug fix
• Refactor
• Tests
• CI/CD
• Documentation

Testing

• Unit tests added/updated — N/A, no app code touched
• Integration tests added/updated — N/A
• Manual testing performed — confirmed the global skill install at ~/.claude/skills/github-throughput-forecast/ works end-to-end after this removal (separate verification, not part of this repo's history)

Checklist

• Tests pass locally (./gradlew testDebug) — N/A, no app code (app/) touched
• No API keys or secrets in code — pure deletion
• CLAUDE.md updated (if new pattern introduced) — not applicable, this removes a pattern rather than introducing one

See Documentation/work-log/666-remove-vendored-throughput-forecast.md for the full writeup.

[Michael Gonzalez (MicGon7)]

Look good 👍

[troymyree-lang]

Approve — clean resolution of the skill-location thread. Deleting the vendored throughput-forecast files and installing the skill globally (~/.claude/skills/github-throughput-forecast/) is the right call: it works for any GitHub Projects board without committing into an app repo, create-ticket stays untouched, and #665's fixes were carried into the global install. Pure forward delete, no app code or secrets.

Merging via admin bypass since the org-required "Required Secret Scan (TruffleHog)" check is stuck pending (org-config issue — a public repo can't invoke the private-repo workflow), being routed to org admins separately.