diff --git a/.planning/ROADMAP.md b/.planning/ROADMAP.md
index b9f4372..1444589 100644
--- a/.planning/ROADMAP.md
+++ b/.planning/ROADMAP.md
@@ -670,7 +670,7 @@ Plans:
   4. Deferred binding: on an unsaved parent, uploads and related-record changes bind to a session key, are committed in the parent's create transaction, and are discarded with the session. Orphaned deferred bindings and their files are purged.
   5. The new code has unit tests, delivered in the phase's last plan, and the docs checker passes.
 
-**Plans:** 3/5 plans executed
+**Plans:** 4/5 plans executed
 
 Plans:
 **Wave 1**
@@ -683,7 +683,7 @@ Plans:
 - [x] 12.2-03-PLAN.md — cabana relation child CRUD (hasMany kind, manage/view/pivot forms, toolbar buttons), D-15 parent scoping, unsaved-parent deferral and relation commit, child file routes
 
 **Wave 4** *(blocked on Wave 3 completion)*
-- [ ] 12.2-04-PLAN.md — Admin SPA: FileuploadField, DatepickerField (Reka), child and pivot modals, create-screen deferral, date/time cells, rebuilt dist
+- [x] 12.2-04-PLAN.md — Admin SPA: FileuploadField, DatepickerField (Reka), child and pivot modals, create-screen deferral, date/time cells, rebuilt dist
 
 **Wave 5** *(blocked on Wave 4 completion)*
 - [ ] 12.2-05-PLAN.md — Unit and security tests (D-15 suite, test map, SPA backstops), check-phase12.2.sh, security review, v0.1.1 tag checkpoint
diff --git a/.planning/STATE.md b/.planning/STATE.md
index 3e88d55..aa4938b 100644
--- a/.planning/STATE.md
+++ b/.planning/STATE.md
@@ -4,16 +4,16 @@ milestone: v1.0
 current_phase: "12.2"
 current_phase_name: "Admin form fields: date, file upload, relation editing with deferred binding (INSERTED)"
 status: executing
-stopped_at: Completed 12.2-03-PLAN.md
-last_updated: "2026-10-02T17:09:43.302Z"
+stopped_at: Completed 12.2-04-PLAN.md
+last_updated: "2026-10-02T17:58:33.905Z"
 last_activity: 2026-10-02
 last_activity_desc: Phase 12.2 execution started
-state_head: 6cdfbd49d047d23f4112286120dd9bfd36164b8d
+state_head: 92d665f1b210648254f5bc3b4e7115302c3c3669
 progress:
   total_phases: 21
   completed_phases: 11
-  total_plans: 106
-  completed_plans: 104
+  total_plans: 108
+  completed_plans: 105
 milestone_name: milestone
 ---
 
@@ -29,7 +29,7 @@ See: .planning/PROJECT.md (updated 2026-09-16)
 ## Current Position
 
 Phase: 12.2 (Admin form fields: date, file upload, relation editing with deferred binding (INSERTED)) — EXECUTING
-Plan: 4 of 5
+Plan: 5 of 5
 Status: Ready to execute
 Last activity: 2026-10-02 — Phase 12.2 execution started
 
@@ -159,6 +159,7 @@ Progress: [██████░░░░] 60%
 | Phase 12.2 P01 | 20min | 3 tasks | 32 files |
 | Phase 12.2 P02 | 28min | 3 tasks | 29 files |
 | Phase 12.2 P03 | 45min | 3 tasks | 26 files |
+| Phase 12.2 P04 | 2h | 4 tasks | 31 files |
 
 ## Accumulated Context
 
@@ -472,6 +473,10 @@ Recent decisions affecting current work:
 - [Phase 12.2]: 12.2-03: at commit, a bind of a child the session created attaches directly; a bind of an existing record re-runs the full link eligibility, and an ineligible one is a 422 on the relation-manager field
 - [Phase 12.2]: 12.2-03: pivot values fill through the pivot form's writable fields only; unknown pivot keys are 422 on link and on PUT .../pivot/{child}
 - [Phase 12.2]: 12.2-03: child file routes use X-Child-Session-Key; a saved child needs update to write files (403), child 0 needs create (404 otherwise)
+- [Phase 12.2]: 12.2-04: the user approved @internationalized/date 3.12.4 as an exact-pinned direct admin dependency
+- [Phase 12.2]: 12.2-04: by user decision, existing belongsToMany relation managers stay deferrable and appear on the create screen unless the relation-manager field has context: update; the create-screen deferral UI is not opt-in
+- [Phase 12.2]: 12.2-04: the registry resolves RelationManager lazily because child forms close an import cycle with it
+- [Phase 12.2]: 12.2-04: a datetime is emitted as UTC YYYY-MM-DDTHH:MM:SSZ without milliseconds; a stored datetime without a zone is read as UTC
 
 ### Pending Todos
 
@@ -520,6 +525,6 @@ Items acknowledged and carried forward from previous milestone close:
 
 ## Session Continuity
 
-Last session: 2026-10-02T17:09:42.798Z
-Stopped at: Completed 12.2-03-PLAN.md
+Last session: 2026-10-02T17:58:33.426Z
+Stopped at: Completed 12.2-04-PLAN.md
 Resume file: None
diff --git a/.planning/state.json b/.planning/state.json
index 51222b9..3d79cc4 100644
--- a/.planning/state.json
+++ b/.planning/state.json
@@ -94,5 +94,5 @@
     "label": "Advance to the next step",
     "reason": "Phase 12.2 of 21 · executing"
   },
-  "updated_at": "2026-10-02T17:09:38.368Z"
+  "updated_at": "2026-10-02T17:58:23.800Z"
 }