[Fix] Warn when scan_hashtype forces software SHA-256 on non-SHA-NI CPU

When scan_hashtype is explicitly set to "sha256" or "both" on a system
without SHA-NI hardware acceleration, SHA-256 runs ~30% slower than MD5
in software. Previously this was silent — the admin had no indication
their override was costing performance.

Now logs a NOTICE (not a fallback — the admin's explicit choice is
honored) when _sha_capability="software" and scan_hashtype is sha256
or both, advising them to consider scan_hashtype=auto.

The default scan_hashtype=auto is unaffected — it already correctly
selects SHA-256 only with hardware support and MD5 otherwise.

Author: rfxn

files/internals/lmd_init.sh

@@ -59,6 +59,9 @@ _resolve_hashtype() {
 				eout "{scan} WARNING: scan_hashtype=sha256 but sha256sum not found, falling back to md5" 1
 				_effective_hashtype="md5"
 			else
+				if [ "$_sha_capability" == "software" ]; then
+					eout "{scan} NOTICE: scan_hashtype=sha256 without hardware SHA-NI — software SHA-256 is ~30% slower than MD5; consider scan_hashtype=auto" 1
+				fi
 				_effective_hashtype="sha256"
 			fi
 			;;
@@ -67,6 +70,9 @@ _resolve_hashtype() {
 				eout "{scan} WARNING: scan_hashtype=both but sha256sum not found, falling back to md5" 1
 				_effective_hashtype="md5"
 			else
+				if [ "$_sha_capability" == "software" ]; then
+					eout "{scan} NOTICE: scan_hashtype=both without hardware SHA-NI — SHA-256 pass will use slower software hashing" 1
+				fi
 				_effective_hashtype="both"
 			fi
 			;;