[Fix] nvm_normalize_lts: only reject uppercase for LTS names, not regular aliases

The lowercase check was in the `*` catch-all branch of the `case` statement, rejecting any alias name with uppercase characters.
This prevented creating or reading uppercase aliases like `TESTY`.
The check should only apply to `lts/*` patterns, since LTS codenames are always lowercase.

Fixes #3764.
Bug introduced in 9fb9dec710 as part of fixing #3417.

nvm.sh

@@ -935,10 +935,14 @@ nvm_normalize_lts() {
       fi
     ;;
     *)
-      if [ "${LTS}" != "$(echo "${LTS}" | command tr '[:upper:]' '[:lower:]')" ]; then
-        nvm_err 'LTS names must be lowercase'
-        return 3
-      fi
+      case "${LTS}" in
+        lts/*)
+          if [ "${LTS}" != "$(echo "${LTS}" | command tr '[:upper:]' '[:lower:]')" ]; then
+            nvm_err 'LTS names must be lowercase'
+            return 3
+          fi
+        ;;
+      esac
       nvm_echo "${LTS}"
     ;;
   esac

test/fast/Aliases/uppercase alias names should work

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+die () { echo "$@" ; cleanup ; exit 1; }
+
+cleanup() {
+  rm -f "$(nvm_alias_path)/UPPER_ALIAS"
+  rm -f "$(nvm_alias_path)/MixedCase"
+}
+
+: nvm.sh
+\. ../../../nvm.sh
+
+\. ../../common.sh
+
+make_fake_node v0.0.1
+
+# Uppercase alias should be created and readable
+nvm alias UPPER_ALIAS v0.0.1
+[ -f "$(nvm_alias_path)/UPPER_ALIAS" ] || die "uppercase alias file should exist"
+
+try nvm_alias UPPER_ALIAS
+[ "${CAPTURED_EXIT_CODE}" = "0" ] || die "nvm_alias should succeed for uppercase alias, got exit code ${CAPTURED_EXIT_CODE}"
+[ "${CAPTURED_STDOUT}" = "v0.0.1" ] || die "nvm_alias UPPER_ALIAS should return v0.0.1, got ${CAPTURED_STDOUT}"
+
+# Mixed case should also work
+nvm alias MixedCase v0.0.1
+[ -f "$(nvm_alias_path)/MixedCase" ] || die "mixed case alias file should exist"
+
+try nvm_alias MixedCase
+[ "${CAPTURED_EXIT_CODE}" = "0" ] || die "nvm_alias should succeed for mixed case alias, got exit code ${CAPTURED_EXIT_CODE}"
+
+# LTS names with uppercase should still be rejected
+try_err nvm_normalize_lts "lts/ARGON"
+[ "${CAPTURED_EXIT_CODE}" = "3" ] || die "uppercase LTS name should fail with exit code 3, got ${CAPTURED_EXIT_CODE}"
+[ "${CAPTURED_STDERR}" = "LTS names must be lowercase" ] || die "expected lowercase error, got ${CAPTURED_STDERR}"
+
+cleanup