Add open-source hygiene note to paperclip-dev skill (#4541)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies.
> - The `paperclip-dev` skill is part of the contributor and agent
workflow layer that tells developers how to work in this repository
safely.
> - That skill already references the public upstream `origin`, but it
did not explicitly say that pushes there must be treated as publishable
open-source output.
> - Without that reminder, contributors are more likely to leak secrets,
PII, private logs, machine-local config, or noisy throwaway git history
into the public repo.
> - This pull request adds a prominent `OPEN SOURCE HYGIENE` callout
near the top of the skill, before the git workflow guidance.
> - The benefit is clearer safety guidance for contributors and less
accidental disclosure or branch/commit noise on the upstream project.

## What Changed

- Added an `OPEN SOURCE HYGIENE` callout near the top of
`skills/paperclip-dev/SKILL.md`.
- Explicitly warned that anything pushed to `origin` must be
publishable.
- Called out avoiding secrets, API keys, PII, private logs,
machine-local config, and noisy throwaway branches or checkpoint
commits.

## Verification

- N/a

## Risks

- Low risk. This is a docs-only change in a skill file; the main risk is
wording tone or placement, not runtime behavior.

## Model Used

- OpenAI Codex via the `codex_local` Paperclip adapter, GPT-5-based
coding agent runtime. Exact backend serving model ID is not exposed in
this heartbeat environment. Tool use, shell execution, and patch
application were enabled.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [ ] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

skills/paperclip-dev/SKILL.md

@@ -12,6 +12,8 @@ description: >
 
 This skill covers the day-to-day workflows for developing and operating a local Paperclip instance. It assumes you are working inside the Paperclip repo checkout with `origin` pointing to `git@github.com:paperclipai/paperclip.git`.
 
+> **OPEN SOURCE HYGIENE:** This repository is public-facing. Treat anything you push to `origin` as publishable. Never commit or push secrets, API keys, tokens, private logs, PII, customer data, or machine-local configuration that should stay private. Keep git history tidy as well: avoid pushing throwaway branches, noisy checkpoint commits, or speculative work that does not need to be shared upstream.
+
 > **MANDATORY:** Before running any CLI command, building, testing, or managing worktrees, you MUST read `doc/DEVELOPING.md` in the Paperclip repo. It is the canonical reference for all `paperclipai` CLI commands, their options, build/test workflows, database operations, worktree management, and diagnostics. Do NOT guess at flags or options — read the doc first.
 
 ## Quick Command Reference