chore: backfill stale doc references after Phase 2 doc-consistency rollout (#29)

The release-doc-sync action (Developer-Tools-Directory v1.8.x) was
integrated in Phase 2c and now auto-maintains CHANGELOG.md and
CLAUDE.md on each release. The existing gap between v1.0.0 and v1.3.x
(current) was not auto-filled.

This PR bridges that gap with honest documentation:
- CHANGELOG.md gets a single "[Versions 1.0.1 through 1.2.x]"
  entry pointing to GitHub releases
- CLAUDE.md hardcoded version references updated to current
- standards-version marker preserved

No code or workflow changes. Documentation only.

Refs TMHSDigital/Developer-Tools-Directory#5.

Signed-off-by: 154358121+TMHSDigital@users.noreply.github.com
Made-with: Cursor

Signed-off-by: 154358121+TMHSDigital@users.noreply.github.com

Author: TMHSDigital

CHANGELOG.md

@@ -21,6 +21,17 @@ See [release notes](https://github.com/TMHSDigital/Docker-Developer-Tools/releas
 
 See [release notes](https://github.com/TMHSDigital/Docker-Developer-Tools/releases/tag/v1.3.0) for details.
 
+## [Versions 1.0.1 through 1.2.x] - prior to 2026-04-25
+
+Multiple patch and minor releases shipped between v1.0.0 and v1.3.0
+without CHANGELOG entries due to release-doc-sync automation
+not yet existing. See [GitHub releases](https://github.com/TMHSDigital/Docker-Developer-Tools/releases)
+for the complete release history.
+
+Going forward, release-doc-sync@v1.0 from
+[TMHSDigital/Developer-Tools-Directory](https://github.com/TMHSDigital/Developer-Tools-Directory)
+automatically maintains this file on each auto-release.
+
 ## [1.0.0] - 2026-03-29
 
 ### Changed