feat(api): fleet data model Phase A — License -> Host -> Instance

Migration 022 adds agent_hosts / game_instances / instance_clusters /
instance_stats (named agent_hosts to avoid the existing B2B hosts
table). HostAgentConsumerService now parses the full v2 heartbeat and
upserts an agent_hosts row (host metrics: cpu/mem/disk/agent version,
keyed by license_id+hostname until enrollment) plus one game_instances
row per heartbeat instance entry (state + uptime, the billing unit).
Legacy server_connections write retained so the current panel keeps
working — additive migration, nothing breaks. Staleness sweep + offline
beacon now flip agent_hosts too. cluster_id FK reserved for Soulmask/
Dune. Migration applied to live DB; tsc green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/migrations/022_fleet_model.sql

@@ -0,0 +1,102 @@
+-- Fleet data model — License → Host → Instance (with optional Cluster)
+--
+-- ADDITIVE: existing server_connections / server_config / server_stats are
+-- left untouched so the current single-server panel keeps working. The
+-- host-agent consumer writes BOTH the legacy connection row and these fleet
+-- tables during the transition; the panel migrates to the fleet tables in a
+-- later phase.
+--
+-- Shape mirrors the host agent's wire protocol v2 heartbeat:
+--   host{} block          → agent_hosts
+--   instances[] entries   → game_instances
+-- Host metrics (CPU/RAM/disk) live on the HOST, not duplicated per instance.
+--
+-- Named `agent_hosts` (not `hosts`) to avoid collision with the existing B2B
+-- `hosts` table (hosting-partner companies) — different concept entirely.
+
+-----------------------------------------------------------
+-- AGENT_HOSTS — one Corrosion host agent / one machine
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS agent_hosts (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    -- Natural key until enrollment issues a stable host identity.
+    hostname VARCHAR(255) NOT NULL DEFAULT '',
+    agent_version VARCHAR(64),
+    agent_commit VARCHAR(64),
+    os VARCHAR(32),
+    arch VARCHAR(32),
+    status VARCHAR(20) NOT NULL DEFAULT 'offline'
+        CHECK (status IN ('connected', 'degraded', 'offline')),
+    last_heartbeat_at TIMESTAMPTZ,
+    cpu_percent DOUBLE PRECISION,
+    cpu_cores INTEGER,
+    mem_total_mb BIGINT,
+    mem_used_mb BIGINT,
+    uptime_seconds BIGINT,
+    disks JSONB,  -- [{ "mount": "/", "total_mb": n, "free_mb": n }]
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (license_id, hostname)
+);
+CREATE INDEX IF NOT EXISTS idx_agent_hosts_license ON agent_hosts(license_id);
+
+-----------------------------------------------------------
+-- INSTANCE CLUSTERS — optional grouping (Soulmask main/child, Dune battlegroup)
+-- Reserved now; cluster logic ships with those game adapters.
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS instance_clusters (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    game VARCHAR(32) NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    topology VARCHAR(32),  -- main_client | battlegroup
+    config JSONB,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_clusters_license ON instance_clusters(license_id);
+
+-----------------------------------------------------------
+-- GAME INSTANCES — one game server process / orchestrated unit.
+-- The billing unit (plans count instances).
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS game_instances (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    host_id UUID REFERENCES agent_hosts(id) ON DELETE SET NULL,
+    cluster_id UUID REFERENCES instance_clusters(id) ON DELETE SET NULL,
+    -- The agent's instance slug; the NATS subject segment.
+    agent_instance_id VARCHAR(64) NOT NULL,
+    game VARCHAR(32) NOT NULL,
+    label VARCHAR(255),
+    -- running | stopped | starting | stopping | crashed
+    -- | configured | missing_root | unmanaged | unknown
+    state VARCHAR(32) NOT NULL DEFAULT 'unknown',
+    root_path TEXT,
+    uptime_seconds BIGINT NOT NULL DEFAULT 0,
+    last_seen_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (license_id, agent_instance_id)
+);
+CREATE INDEX IF NOT EXISTS idx_instances_license ON game_instances(license_id);
+CREATE INDEX IF NOT EXISTS idx_instances_host ON game_instances(host_id);
+
+-----------------------------------------------------------
+-- INSTANCE STATS — per-instance time series (game metrics).
+-- Populated once game-level telemetry (player count/FPS via RCON/plugin) is
+-- collected; the host heartbeat carries host metrics, not game metrics.
+-----------------------------------------------------------
+CREATE TABLE IF NOT EXISTS instance_stats (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    instance_id UUID NOT NULL REFERENCES game_instances(id) ON DELETE CASCADE,
+    license_id UUID NOT NULL REFERENCES licenses(id) ON DELETE CASCADE,
+    player_count INTEGER NOT NULL DEFAULT 0,
+    max_players INTEGER NOT NULL DEFAULT 0,
+    fps DOUBLE PRECISION NOT NULL DEFAULT 0,
+    memory_usage_mb INTEGER NOT NULL DEFAULT 0,
+    recorded_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_instance_stats_instance
+    ON instance_stats(instance_id, recorded_at DESC);