docs(P00): create phase 1 plan — 10 slices, 4 waves, 34 tasks, 20/20 REQ coverage

PLAN.md: 998 lines (vertical-slice plan with wave ordering)
.gitignore: fix .env.example being ignored by .env.* pattern (D-038)

Wave 1: Dockerfile + docker-compose.yml + .dockerignore | FastAPI StaticFiles mount
Wave 2: PVE API layer (8 scripts) | health-check.sh
Wave 3: firstboot-hook.sh | install-service.sh + praxis.service | lxc-deploy.sh
Wave 4: secret wiring + .env.example | bats tests (11 files) | E2E verification

Persona load: devops-engineer 15 tasks, lead-developer 4, backend 4, data 2, frontend 0 (deactivated)

---ci---
project: praxis
phase: 0
milestone: v0.2
status: plan
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,20 +1,14 @@
 {
   "phase": 0,
-  "stage": "research",
+  "stage": "plan",
   "milestone": "v0.2",
   "phase_role": "pre_execution",
   "attempts": 0,
-  "updated_at": "2026-08-01T14:15:00Z",
-  "research_confidence": {
-    "docker_in_lxc": 0.85,
-    "build_inside_ct": 0.80,
-    "fastapi_staticfiles": 0.95,
-    "dockerfile_design": 0.90,
-    "firstboot_hook": 0.85,
-    "secret_injection": 0.90,
-    "health_check": 0.90,
-    "systemd_unit": 0.85,
-    "ct_sizing": 0.80,
-    "testing": 0.90
+  "updated_at": "2026-08-01T14:25:00Z",
+  "plan_summary": {
+    "slices": 10,
+    "waves": 4,
+    "tasks": 34,
+    "req_coverage": "20/20"
   }
 }