chore: align module folder names and artifactIds to platform naming convention

[mdproctor]

Summary

Apply the platform module naming convention (PP-20260508-5c0e4b) to devtown:

• Folder names → short descriptive names (no repo prefix)
• artifactIds → fully qualified casehub-devtown-* prefix
• Root parent artifactId → casehub-devtown-parent

Changes

Folder renames (git mv + root pom module entries)

Current	Should be
devtown-domain/	domain/
devtown-review/	review/
devtown-queue/	queue/
devtown-github/	github/
devtown-app/	app/

POM coordinate changes

Artifact	Current	Should be
Root parent	casehub-devtown	casehub-devtown-parent
domain module	devtown-domain	casehub-devtown-domain
review module	devtown-review	casehub-devtown-review
queue module	devtown-queue	casehub-devtown-queue
github module	devtown-github	casehub-devtown-github
app module	devtown-app	casehub-devtown-app

References

Protocol: docs/protocols/maven-submodule-folder-naming.md (PP-20260508-5c0e4b)
Plan: ~/claude/public/casehub/plans/module-naming-alignment.md