docs(init): validate v0.5 specification

---ci---
project: orca
phase: 0
milestone: v0.5
status: specify
---/ci---

.ciagent/ROADMAP.md

@@ -69,3 +69,22 @@ Per `.ciagent/RELEASE_POLICY.md`, every phase tag produces a Gitea release.
 The vision ("minimalist, offline-first, CLI-first orchestration
 engine") is unchanged. v0.3 closes out the v0.2 deferrals and merges
 the accumulated v0.2 work to main.
+
+## Milestone v0.5: Distribution — **IN PROGRESS**
+
+Scope: make Orca installable, distributable, and containerized. The
+engine functionality from v0.1–v0.3 is unchanged; this milestone is
+purely about delivery surface.
+
+- [ ] Phase 0: Pre-execution (specify → clarify → research → plan → grill) — tag `v0.4.1`
+- [ ] Phase 1: Namespace unification (`ORCA_HOME` + `--system`) (REQ-041, REQ-042) — tag `v0.4.2`
+- [ ] Phase 2: `install.sh` + in-place update + README quickstart (REQ-043, REQ-044) — tag `v0.4.3`
+- [ ] Phase 3: Docker release (Dockerfile + Gitea container registry) (REQ-046) — tag `v0.4.4`
+- [ ] Phase 4: Final review + ship + audit (milestone release) — tag `v0.4.5` (promoted to `v0.5.0`)
+
+**Operational prerequisite (P0 ship)**: flip Gitea repo visibility to
+public via `tea repos edit coreci/orca --private=false` (REQ-045) so
+that `install.sh` can pull release binaries unauthenticated.
+
+**Milestone tag**: `v0.5.0` (next-minor per feature-milestone promotion rule).
+Per-phase tags run on the v0.4.x patch line (`v0.4.1`…`v0.4.5`).