enhance: Improve validation errors for secrets/variables (#39221)

Signed-off-by: Ross Golder <ross@golder.org>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

options/locale/locale_en-US.json

@@ -3751,11 +3751,10 @@
   "secrets.description": "Secrets will be passed to certain actions and cannot be read otherwise.",
   "secrets.none": "There are no secrets yet.",
   "secrets.creation.description": "Description",
-  "secrets.creation.name_placeholder": "case-insensitive, alphanumeric characters or underscores only, cannot start with GITEA_ or GITHUB_",
+  "secrets.creation.name_pattern": "Name must start with a letter or underscore, contain only letters, numbers, and underscores, and must not start with GITEA_ or GITHUB_",
   "secrets.creation.value_placeholder": "Input any content. Whitespace at the start and end will be omitted.",
   "secrets.creation.description_placeholder": "Enter short description (optional).",
   "secrets.save_success": "The secret \"%s\" has been saved.",
-  "secrets.save_failed": "Failed to save secret.",
   "secrets.add_secret": "Add secret",
   "secrets.edit_secret": "Edit secret",
   "secrets.deletion": "Remove secret",
@@ -3932,9 +3931,7 @@
   "actions.variables.edit": "Edit Variable",
   "actions.variables.deletion.failed": "Failed to remove variable.",
   "actions.variables.deletion.success": "The variable has been removed.",
-  "actions.variables.creation.failed": "Failed to add variable.",
   "actions.variables.creation.success": "The variable \"%s\" has been added.",
-  "actions.variables.update.failed": "Failed to edit variable.",
   "actions.variables.update.success": "The variable has been edited.",
   "actions.logs.always_auto_scroll": "Always auto scroll logs",
   "actions.logs.always_expand_running": "Always expand running logs",