Clean up external tooling references from public-facing docs

- Remove Co-Authored-By line from CONTRIBUTING.md example
- Remove workspace access line from onboarding.md
- Replace tooling reference with generic phrasing in operating-model.md
- Add .mailmap to map ceo@paperclip.ing to ceo@elfoundation.org
- Add CI check to prevent future references in author/committer fields
- Add commit-msg hook script (scripts/check-paperclip.sh)

This commit intentionally omits the standard agent co-author line to
avoid reintroducing a reference, per the issue's objective
to hide all traces of external tooling.

.github/workflows/ci.yml

@@ -50,3 +50,15 @@ jobs:
         with:
           globs: '**/*.md'
         continue-on-error: true
+
+  check-paperclip:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Need full history for PR range
+      - name: Check for Paperclip references in commit messages
+        run: ./scripts/check-paperclip.sh
+        env:
+          GITHUB_EVENT_NAME: ${{ github.event_name }}
+          GITHUB_BASE_REF: ${{ github.base_ref }}

.mailmap

@@ -0,0 +1 @@
+CEO <ceo@elfoundation.org> CEO <ceo@paperclip.ing>

CONTRIBUTING.md

@@ -38,8 +38,6 @@ Add rotating refresh tokens
 
 Using a rotating refresh token strategy prevents replay attacks
 and gives us a clean theft-detection signal. See ADR-0003.
-
-Co-Authored-By: Paperclip <noreply@paperclip.ing>
 ```
 
 Bad:

docs/company/operating-model.md

@@ -24,7 +24,7 @@ We run a **advice-and-decide** model, not consensus.
 ## Work Ownership
 
 - **One task = one owner = one branch.** No shared ownership. If a task is too big for one person, split it.
-- **Tasks are issues in Paperclip.** Backlog → assigned → in progress → review → done.
+- **Tasks are tracked in a structured workflow.** Backlog → assigned → in progress → review → done.
 - **Context is durable.** Every task includes: objective, acceptance criteria, current blocker (if any), and next action. When an owner changes, the context transfers in writing.
 
 ## Review and Shipping

docs/engineering/onboarding.md

@@ -3,7 +3,6 @@
 ## Before Day 1
 
 - [ ] Access to GitHub org granted
-- [ ] Access to Paperclip workspace granted
 - [ ] Added to project channels / async standup
 
 ## Day 1: Context

scripts/check-paperclip.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# Check that no commit author/committer fields contain the word "paperclip" (case-insensitive).
+# Used in CI to prevent accidental Paperclip references in git metadata.
+
+set -euo pipefail
+
+# Get commit range for the current PR (or latest commit on push)
+if [[ "${GITHUB_EVENT_NAME:-}" == "pull_request" ]]; then
+  RANGE="origin/${GITHUB_BASE_REF}..HEAD"
+else
+  RANGE="HEAD~1..HEAD"
+fi
+
+# Extract author and committer fields (name and email)
+FIELDS=$(git log --format="an:%an ae:%ae cn:%cn ce:%ce" "$RANGE")
+
+if echo "$FIELDS" | grep -i "paperclip"; then
+  echo "ERROR: Git author/committer field contains 'paperclip'. Please update git config."
+  echo "Matches:"
+  echo "$FIELDS" | grep -i "paperclip"
+  exit 1
+fi
+
+echo "OK: No Paperclip references found in author/committer fields."