fix: QA remediation P1-D + P2 for infra/vps orchestrator (v1.8.0)

P1-D: bump package.json version 1.7.2 → 1.8.0 and add [1.8.0] CHANGELOG
entry documenting the infra/vps/ PRAB generation orchestrator addition.

P2 (security): replace StrictHostKeyChecking=no with StrictHostKeyChecking=accept-new
in all three SSH invocations in orchestrate-generation.sh. Add
UserKnownHostsFile=${KNOWN_HOSTS} (-o) to pin key verification to the
pre-seeded file rather than the root known_hosts.

install-orchestrator.sh: add ssh-keyscan step that pre-populates
/opt/prab-orchestrator/known_hosts with Hostinger's host key on first
install. Graceful degradation: if ssh-keyscan fails, logs WARN and
proceeds (accept-new will add the key on first real connect).

prab-generation.service: add justifying comment for User=root (root holds
the Hostinger SSH key + known_hosts in /root/.ssh/ and /opt/prab-orchestrator/).

Agent-Session: prab-reliability-remediation-20260622

package.json

@@ -1,6 +1,6 @@
 {
   "name": "peptide-e2e",
-  "version": "1.7.2",
+  "version": "1.8.0",
   "description": "Playwright smoke tests for peptiderepo.com (staging + production)",
   "private": true,
   "scripts": {