Summary

After the other 7 sub-EPICs in #657 (Phases 1-6 + logger Phase 7) close, audit common_system itself against the published kcenon-system-layout.md and apply any final adjustments.

BLOCKED: This issue is intentionally blocked until all of:

• [Epic] pacs_system: directory structure migration to ecosystem standard pacs_system#1137 (Phase 1)
• [EPIC] database_system: introduce include/ directory and standardize layout database_system#577 (Phase 2)
• [EPIC] container_system: consolidate scattered headers and standardize layout container_system#531 (Phase 3)
• [EPIC] network_system: standardize tests and decompose CMake network_system#1083 (Phase 4)
• [EPIC] monitoring_system: remove legacy fallback and decompose CMake monitoring_system#674 (Phase 5)
• [EPIC] thread_system: absorb legacy directories into standard layout thread_system#683 (Phase 6)
• [EPIC] logger_system: final standard verification logger_system#624 (Phase 7)

are closed. Do not pick up early.

Part of #656.

Why

• common_system sits at the dependency-graph root; auditing it last avoids cascading rebuilds during sibling migrations
• A final sweep catches drift accumulated while siblings adapted to the standard
• Closing the master EPIC requires this verification

Scope

1. Run the layout standard checklist against the current common_system tree
2. Verify cmake template adoption is current with the latest template version
3. Confirm cross-build CI is green across all 8 systems
4. Update master EPIC [EPIC] Ecosystem-wide directory structure standardization #657 body with the final verification note

Acceptance Criteria

• Checklist run and any deviations either fixed or explicitly documented as exceptions
• cmake template version recorded in this repo matches the released template version
• Cross-build CI passes on a verification run
• Master EPIC [EPIC] Ecosystem-wide directory structure standardization #657 body updated with "Phase 7 complete" note linking the verification run

Out of Scope

• Modifying the standard itself (changes go through a new minor version of docs(layout): publish kcenon-system-layout.md v1.0 #658)
• Touching sibling repos