docs(P00): fix milestone version v1.0 -> v0.1

---ci---
project: oy
phase: 0
milestone: v0.1
status: complete
---/ci---

Corrects CHECKPOINT.json and PROJECT.md after history rewrite.
Milestone remains v0.1 until MVP ships as v0.1.0.

.ciagent/CHECKPOINT.json

@@ -1,7 +1,7 @@
 {
   "phase": 0,
   "stage": "complete",
-  "milestone": "v1.0",
+  "milestone": "v0.1",
   "phase_role": "pre_execution",
   "attempts": 0,
   "updated_at": "2026-08-17T00:00:00Z"

.ciagent/oy/PROJECT.md

@@ -56,4 +56,4 @@ OpenYield (OY) is a durable, anti-greed, jurisdiction-light financial layer —
 - Phase plans
 
 ## Milestone
-v1.0 — OpenYield Foundation Init
+v0.1 — OpenYield Foundation Init (pre-MVP development milestone; remains v0.1 until MVP ships as v0.1.0)