docs(template): close 9 RSR-template substitution gaps

Echidna was instantiated from rsr-template-repo; nine placeholder
strings never got replaced with echidna-specific values:

CODE_OF_CONDUCT.md
- L61, L111: echidna-conduct@example.org → j.d.a.jewell@open.ac.uk
- L48: "GitLab repositories" prose → "GitHub repository + GitLab CI mirror"

SECURITY.md
- L34: "public GitLab issues" → "public GitHub issues"
- L38, L205: security@echidna-project.org → j.d.a.jewell@open.ac.uk
- L134: same email substitution
- L206: "(when available)" PGP placeholder → fingerprint
  4A03639C1EB1F86C7F0C97A91835A14A2867091E + key fetch instructions
- L207: "@echidna-security (when available)" → @hyperpolymath

AUTHORS.md
- L47: "merge request on GitLab" → "pull request on GitHub"
- L99: malformed GitLab-style URL .../-/issues → /issues
- L100: contributors@echidna-project.org → maintainer email

Also adds SPDX-FileCopyrightText owner line to satisfy pre-commit.

Lane: prover-corpus-saturation. Adjacent to the saturation campaign;
small enough to roll into the same branch.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

AUTHORS.md

@@ -1,4 +1,5 @@
 <!--
+SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 SPDX-License-Identifier: MPL-2.0
 SPDX-FileCopyrightText: 2024-2025 ECHIDNA Project Contributors
 -->
@@ -44,7 +45,7 @@ We would like to extend special thanks to:
 
 If you've contributed to ECHIDNA and your name isn't listed here, please:
 
-1. Open an issue or merge request on GitLab
+1. Open an issue or pull request on GitHub (<https://github.com/hyperpolymath/echidna>)
 2. Provide a brief description of your contribution
 3. Indicate how you'd like to be credited
 
@@ -96,8 +97,8 @@ By contributing to ECHIDNA, you agree to license your contributions under these
 ## Contact
 
 For questions about attribution or contributions:
-- GitLab Issues: https://github.com/hyperpolymath/echidna/-/issues
-- Email: contributors@echidna-project.org (when available)
+- GitHub Issues: <https://github.com/hyperpolymath/echidna/issues>
+- Email: j.d.a.jewell@open.ac.uk (maintainer; community contributor list opens when first PR lands)
 
 ---
 

CODE_OF_CONDUCT.md

@@ -1,4 +1,5 @@
 <!--
+SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 SPDX-License-Identifier: MPL-2.0
 SPDX-FileCopyrightText: 2024-2025 ECHIDNA Project Contributors
 -->
@@ -45,7 +46,7 @@ Project maintainers have the right and responsibility to remove, edit, or reject
 
 This Code of Conduct applies within all project spaces, including:
 
-- GitLab repositories (code, issues, merge requests, wiki)
+- GitHub repository (code, issues, pull requests, wiki) and any mirror (e.g. GitLab CI mirror)
 - Project communication channels (mailing lists, chat, forums)
 - Official project events (conferences, meetups, workshops)
 - Social media when representing the project
@@ -58,7 +59,7 @@ It also applies when an individual is officially representing the project in pub
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the project team at:
 
-**echidna-conduct@example.org** (Replace with actual contact)
+**j.d.a.jewell@open.ac.uk**
 
 All complaints will be reviewed and investigated promptly and fairly.
 
@@ -108,4 +109,4 @@ For answers to common questions about this code of conduct, see the FAQ at https
 
 **Version**: 1.0
 **Last Updated**: 2025-11-22
-**Contact**: echidna-conduct@example.org (Replace with actual contact)
+**Contact**: j.d.a.jewell@open.ac.uk

SECURITY.md

@@ -1,4 +1,5 @@
 <!--
+SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 SPDX-License-Identifier: MPL-2.0
 SPDX-FileCopyrightText: 2024-2025 ECHIDNA Project Contributors
 -->
@@ -31,11 +32,11 @@ We take the security of ECHIDNA seriously. If you believe you have found a secur
 
 ### Where to Report
 
-**DO NOT** report security vulnerabilities through public GitLab issues.
+**DO NOT** report security vulnerabilities through public GitHub issues.
 
 Instead, please report them via email to:
 
-**security@echidna-project.org** (Replace with actual security contact)
+**j.d.a.jewell@open.ac.uk** (GPG-encrypted preferred — see Contact section below for key fingerprint)
 
 ### What to Include
 
@@ -130,9 +131,9 @@ Security updates are released as:
 
 Security advisories are published at:
 
-- **GitLab**: https://github.com/hyperpolymath/echidna/-/security/advisories
-- **Email**: Subscribers to security@echidna-project.org
-- **RSS**: Security advisory feed (when available)
+- **GitHub Security Advisories**: <https://github.com/hyperpolymath/echidna/security/advisories>
+- **Email**: Subscribers to j.d.a.jewell@open.ac.uk (private notification list)
+- **GitHub Releases atom feed**: <https://github.com/hyperpolymath/echidna/releases.atom>
 
 ## Scope
 
@@ -202,9 +203,9 @@ The following are typically not accepted:
 
 For security-related questions or concerns:
 
-- **Email**: security@echidna-project.org (Replace with actual contact)
-- **PGP Key**: Available at https://keys.openpgp.org (when available)
-- **GitLab**: @echidna-security (when available)
+- **Email**: j.d.a.jewell@open.ac.uk
+- **PGP Key**: fingerprint `4A03639C1EB1F86C7F0C97A91835A14A2867091E` — fetch via `gpg --recv-keys 4A03639C1EB1F86C7F0C97A91835A14A2867091E` or from <https://keys.openpgp.org/search?q=j.d.a.jewell@open.ac.uk>
+- **GitHub**: [@hyperpolymath](https://github.com/hyperpolymath)
 
 ## Acknowledgments