feat: add swarm-common obsidian vault

Add Obsidian vault to the swarm-common virtiofs share for access
from zap VM and other VMs. Contains agent memory, notes, and
infrastructure documentation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

swarm-common/obsidian-vault/zap/memory/startup-health.json

@@ -0,0 +1,25 @@
+{
+  "last_run_utc": "2026-03-09T17:31:00Z",
+  "status": "warn",
+  "checks_passed": [
+    "workspace_files_present",
+    "required_skill_folders_present",
+    "tasks_state_present",
+    "required_hooks_ready",
+    "permissions_ok_home_and_credentials",
+    "gateway_local_only_listener",
+    "expected_service_posture_ok",
+    "backup_signal_fresh_within_8h",
+    "security_audit_fresh_within_24h",
+    "update_status_checked"
+  ],
+  "checks_failed": [],
+  "warnings": [
+    "security_audit_warn: security.trust_model.multi_user_heuristic",
+    "update_available: npm 2026.3.8"
+  ],
+  "gateway_exposure": "local-only",
+  "last_backup_age_hours": 5.44,
+  "last_security_audit_age_hours": 0.0,
+  "update_status": "available (npm 2026.3.8)"
+}