plan: add Phase 1 implementation plan for CodexHelper (milestones, deliverables, acceptance criteria)

docs/devlog/DEVLOG_HUMAN.md

@@ -143,3 +143,30 @@ Details:
 
 Next Steps:
 - Apply this propagation practice for future non-project-specific instructions.
+
+---
+
+Date: 2025-09-17 16:00 (UTC)
+
+Summary:
+- Committed and pushed all recent changes; verified local is in sync with remote.
+
+Details:
+- Conventional Commits used; pushed to `origin main`.
+- Verified `HEAD` equals `origin/main` and working tree is clean.
+
+Next Steps:
+- Await proposal approval; then draft `collab/plan/01-codexhelper.md`.
+
+---
+
+Date: 2025-09-17 16:05 (UTC)
+
+Summary:
+- Created Phase 1 implementation plan for CodexHelper.
+
+Details:
+- Added `collab/plan/01-codexhelper.md` and `.llm.md` with milestones, deliverables, and acceptance criteria aligned to the approved proposal.
+
+Next Steps:
+- Await plan review/approval; then start implementation.