v3.42.11: Replace all Unicode emojis with ASCII text

- Replace all emoji characters with ASCII equivalents throughout codebase
- Replace Unicode box-drawing characters (═║╔╗╚╝━─) with ASCII (+|-=)
- Replace checkmarks (✓✗) with [OK]/[FAIL] markers
- 59 files updated, 741 lines changed
- Improves terminal compatibility and reduces visual noise

internal/security/privileges.go

@@ -25,7 +25,7 @@ func (pc *PrivilegeChecker) CheckAndWarn(allowRoot bool) error {
 	isRoot, user := pc.isRunningAsRoot()
 
 	if isRoot {
-		pc.log.Warn("⚠️  Running with elevated privileges (root/Administrator)")
+		pc.log.Warn("[WARN] Running with elevated privileges (root/Administrator)")
 		pc.log.Warn("Security recommendation: Create a dedicated backup user with minimal privileges")
 
 		if !allowRoot {

internal/security/resources.go

@@ -64,7 +64,7 @@ func (rc *ResourceChecker) ValidateResourcesForBackup(estimatedSize int64) error
 
 	if len(warnings) > 0 {
 		for _, warning := range warnings {
-			rc.log.Warn("⚠️  Resource constraint: " + warning)
+			rc.log.Warn("[WARN] Resource constraint: " + warning)
 		}
 		rc.log.Info("Continuing backup operation (warnings are informational)")
 	}

internal/security/resources_unix.go

@@ -22,7 +22,7 @@ func (rc *ResourceChecker) checkPlatformLimits() (*ResourceLimits, error) {
 		rc.log.Debug("Resource limit: max open files", "limit", rLimit.Cur, "max", rLimit.Max)
 
 		if rLimit.Cur < 1024 {
-			rc.log.Warn("⚠️  Low file descriptor limit detected",
+			rc.log.Warn("[WARN] Low file descriptor limit detected",
 				"current", rLimit.Cur,
 				"recommended", 4096,
 				"hint", "Increase with: ulimit -n 4096")