docs: add missing version comparison links to CHANGELOG

v1.0.2, v1.0.3, v1.0.4 were missing from the reference link block at
the bottom of CHANGELOG.md, breaking Keep a Changelog conventions.

Author: AlbinoGeek

CHANGELOG.md

@@ -282,6 +282,9 @@ Initial public tool surface: `repo_status`, `my_work`, `pr_preflight`,
 `release_readiness`, `ci_diagnosis`, `org_pulse`, `pin_drift`,
 `ecosystem_activity`, `module_pin_hint`.
 
+[1.0.4]: https://github.com/Rethunk-AI/rethunk-github-mcp/compare/v1.0.3...v1.0.4
+[1.0.3]: https://github.com/Rethunk-AI/rethunk-github-mcp/compare/v1.0.2...v1.0.3
+[1.0.2]: https://github.com/Rethunk-AI/rethunk-github-mcp/compare/v1.0.1...v1.0.2
 [1.0.1]: https://github.com/Rethunk-AI/rethunk-github-mcp/compare/v1.0.0...v1.0.1
 [1.0.0]: https://github.com/Rethunk-AI/rethunk-github-mcp/releases/tag/v1.0.0
 [0.3.0]: https://github.com/Rethunk-AI/rethunk-github-mcp/releases/tag/v0.3.0