docs(P00): create v0.8 phase plans — 4 exec phases + final review

PLAN_v0.8.md (33KB): 4 execution phases, 37 tasks (36 must-haves),
3-wave ordering per phase, persona-assigned (lead/backend/data),
REQ-057..060 mapped.

P01 coverage round 2 (12 tasks): proxmox sessionRunner seam + 9 pkg
tests, tiered floor ≥70%/≥50% per D-047.
P02 SSH trust (11 tasks): --host-key-fingerprint pre-pin + key-reset +
TOFU capture bugfix + HostKeyFingerprint population.
P03 verify-reqs gate (5 tasks): cmd/verify-reqs Go program + make
target + .coreci.yml hook.
P04 final review + ship + audit (9 tasks).

Zero new direct deps. ROADMAP reconciled to 4-phase structure (P04 =
final review, no separate P05).

---ci---
project: orca
phase: 0
milestone: v0.8
status: plan
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,11 +1,11 @@
 {
   "phase": 0,
-  "stage": "research",
+  "stage": "plan",
   "milestone": "v0.8",
   "milestone_slug": "coverage-trust-hardening",
   "phase_role": "pre_execution",
   "attempts": 0,
-  "updated_at": "2026-08-04T00:45:00Z",
+  "updated_at": "2026-08-04T00:46:00Z",
   "milestone_complete": false,
   "next_milestone": null
 }