Complete private Monero miner control stack.

Implement Windows agent with RandomX mining and WebSocket fleet reporting, wire dashboard settings into the builder with saved exe paths, and add project README.

agent/miner/target.go

@@ -0,0 +1,53 @@
+package miner
+
+import (
+	"encoding/hex"
+	"math/big"
+)
+
+func hashMeetsTarget(hashHex, targetHex string) bool {
+	hashBytes, err := hex.DecodeString(hashHex)
+	if err != nil || len(hashBytes) == 0 {
+		return false
+	}
+	targetBytes, err := hex.DecodeString(padHex(targetHex, len(hashBytes)*2))
+	if err != nil || len(targetBytes) == 0 {
+		return false
+	}
+
+	if len(targetBytes) < len(hashBytes) {
+		padded := make([]byte, len(hashBytes))
+		copy(padded, targetBytes)
+		targetBytes = padded
+	}
+	if len(hashBytes) < len(targetBytes) {
+		padded := make([]byte, len(targetBytes))
+		copy(padded, hashBytes)
+		hashBytes = padded
+	}
+
+	hashInt := new(big.Int).SetBytes(reverseBytes(hashBytes))
+	targetInt := new(big.Int).SetBytes(reverseBytes(targetBytes))
+	return hashInt.Cmp(targetInt) <= 0
+}
+
+func padHex(s string, length int) string {
+	if len(s) >= length {
+		return s
+	}
+	pad := length - len(s)
+	out := make([]byte, length)
+	for i := 0; i < pad; i++ {
+		out[i] = '0'
+	}
+	copy(out[pad:], []byte(s))
+	return string(out)
+}
+
+func reverseBytes(b []byte) []byte {
+	out := make([]byte, len(b))
+	for i := range b {
+		out[i] = b[len(b)-1-i]
+	}
+	return out
+}