checkpoint(p3): v0.4 phase 3 complete → v0.3.3

P3 shipped: tag v0.3.3, release id 751. REQ-032 covered. Branch
oy/phase/03 deleted. All execution phases complete. Next: P4 final
review + audit + milestone ship.

---ci---
project: oy
phase: 3
milestone: v0.4
status: complete
tag_base: v0.3.x
milestone_type: nfr
phase_release_tag: v0.3.3
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,5 +1,5 @@
 {
-  "phase": 2,
+  "phase": 3,
   "stage": "complete",
   "milestone": "v0.4",
   "milestone_type": "nfr",
@@ -7,8 +7,8 @@
   "phase_role": "execution",
   "project": "oy",
   "attempts": 0,
-  "updated_at": "2026-08-17T23:40:00Z",
-  "phase_release_tag": "v0.3.2",
-  "release_id": 750,
-  "reqs_covered": ["REQ-029", "REQ-030", "REQ-031"]
+  "updated_at": "2026-08-17T23:45:00Z",
+  "phase_release_tag": "v0.3.3",
+  "release_id": 751,
+  "reqs_covered": ["REQ-029", "REQ-030", "REQ-031", "REQ-032"]
 }