feat: add tiered startup ordering to first-boot containers

- Tier 1: Databases & Core Infrastructure (Bitcoin, MariaDB, Postgres)
- Tier 2: Core Services (LND, Fedimint) with 5s stabilization delay
- Tier 3: Applications (Home Assistant, Grafana, etc.) with 5s delay
- Matches health_monitor.rs StartupTier approach

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

loop/plan.md

@@ -305,7 +305,7 @@ Every test must pass **10 consecutive times** from BOTH .228→.198 AND .198→.
 
 - [x] **ISO-02** — Added swap creation to first-boot-containers.sh. Calculates 50% of RAM (min 2GB, max 8GB), creates /swapfile, sets permissions 600, mkswap + swapon, adds to /etc/fstab. Skips if swap already exists. Runs before container creation so apps have swap available.
 
-- [ ] **ISO-03** — Add container dependency ordering to first-boot. Same startup ordering as CONT-02 but for the first-boot-containers.sh script. **Acceptance**: Fresh install starts containers in dependency order with zero crash loops.
+- [x] **ISO-03** — Added tiered startup ordering to first-boot-containers.sh. Tier 1: Databases & Core Infrastructure (Bitcoin, MariaDB, Postgres, Electrs). Tier 2: Core Services (LND, Fedimint) with 5s stabilization delay. Tier 3: Applications (Home Assistant, Grafana, etc.) with 5s delay. Matches CONT-02's StartupTier approach.
 
 ---
 

scripts/first-boot-containers.sh

@@ -62,6 +62,9 @@ fi
 # Ensure network exists (matches deploy)
 $DOCKER network create archy-net 2>/dev/null || true
 
+# ── Tier 1: Databases & Core Infrastructure ──────────────────────────────
+log "=== Tier 1: Databases & Core Infrastructure ==="
+
 # 1. Bitcoin Knots (matches deploy exactly)
 if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -qE 'bitcoin-knots|archy-bitcoin-knots'; then
   log "Creating Bitcoin Knots..."
@@ -202,6 +205,10 @@ if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -q btcpay-server; then
     docker.io/btcpayserver/btcpayserver:1.13.5 2>>"$LOG" || true
 fi
 
+# ── Tier 2: Core Services ─────────────────────────────────────────────────
+log "=== Tier 2: Core Services ==="
+sleep 5  # Let databases stabilize
+
 # 4. LND
 if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -qE '^lnd$'; then
   log "Creating LND..."
@@ -296,6 +303,10 @@ if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -q fedimint-gateway; th
   fi
 fi
 
+# ── Tier 3: Applications ──────────────────────────────────────────────────
+log "=== Tier 3: Applications ==="
+sleep 5  # Let core services stabilize
+
 # 6. Home Assistant
 if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -qE 'homeassistant|home-assistant'; then
   log "Creating Home Assistant..."