docs: standardize contact/attribution email to j.d.a.jewell@open.ac.uk (#52)

Standardizes all contact + attribution email references to the canonical
`j.d.a.jewell@open.ac.uk`, replacing the GitHub noreply and the
`jonathan.jewell@open.ac.uk` variant. Octad data records and `.mailmap`
excluded.

https://claude.ai/code/session_017TXizM5c1Yd9HWf7Y15YH2

---
_Generated by [Claude
Code](https://claude.ai/code/session_017TXizM5c1Yd9HWf7Y15YH2)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath

CODE_OF_CONDUCT.md

@@ -120,7 +120,7 @@ If you experience or witness unacceptable behaviour, or have any other concerns,
 
 | Method | Details | Best For |
 |--------|---------|----------|
-| **Email** | 6759885+hyperpolymath@users.noreply.github.com | Detailed reports, sensitive matters |
+| **Email** | j.d.a.jewell@open.ac.uk | Detailed reports, sensitive matters |
 | **Private Message** | Contact any maintainer directly | Quick questions, minor issues |
 | **Anonymous Form** | [Link to form if available] | When you need anonymity |
 
@@ -215,7 +215,7 @@ For contributors with elevated access (Perimeter 2 or 1):
 If you believe an enforcement decision was made in error:
 
 1. **Wait 7 days** after the decision (cooling-off period)
-2. **Email** 6759885+hyperpolymath@users.noreply.github.com with subject line "Appeal: [Original Report ID]"
+2. **Email** j.d.a.jewell@open.ac.uk with subject line "Appeal: [Original Report ID]"
 3. **Explain** why you believe the decision should be reconsidered
 4. **Provide** any new information not previously available
 
@@ -295,7 +295,7 @@ We thank these communities for their leadership in creating welcoming spaces.
 If you have questions about this Code of Conduct:
 
 - Open a [Discussion](https://github.com/hyperpolymath/tangle/discussions) (for general questions)
-- Email 6759885+hyperpolymath@users.noreply.github.com (for private questions)
+- Email j.d.a.jewell@open.ac.uk (for private questions)
 - Contact any maintainer directly
 
 ---

SECURITY.md

@@ -41,7 +41,7 @@ This method ensures:
 ### Alternative: Email
 
 If you cannot use GitHub Security Advisories, email us directly at
-6759885+hyperpolymath@users.noreply.github.com. No PGP key is currently
+j.d.a.jewell@open.ac.uk. No PGP key is currently
 published; for an encrypted channel, request one via a GitHub Security
 Advisory.
 
@@ -354,7 +354,7 @@ When using tangle, we recommend:
 
 | Purpose | Contact |
 |---------|---------|
-| **Security issues** | [Report via GitHub](https://github.com/hyperpolymath/tangle/security/advisories/new) or 6759885+hyperpolymath@users.noreply.github.com |
+| **Security issues** | [Report via GitHub](https://github.com/hyperpolymath/tangle/security/advisories/new) or j.d.a.jewell@open.ac.uk |
 | **General questions** | [GitHub Discussions](https://github.com/hyperpolymath/tangle/discussions) |
 | **Other enquiries** | See [README](README.md) for contact information |