fix(ui): remove misleading model placeholders from input fields

Clear placeholder values for model input fields to avoid suggesting specific model names that may not be applicable to all providers. This prevents user confusion when configuring different Claude providers.

src/components/providers/forms/ClaudeFormFields.tsx

@@ -179,7 +179,7 @@ export function ClaudeFormFields({
                   onModelChange("ANTHROPIC_MODEL", e.target.value)
                 }
                 placeholder={t("providerForm.modelPlaceholder", {
-                  defaultValue: "claude-3-7-sonnet-20250219",
+                  defaultValue: "",
                 })}
                 autoComplete="off"
               />
@@ -200,7 +200,7 @@ export function ClaudeFormFields({
                   onModelChange("ANTHROPIC_DEFAULT_HAIKU_MODEL", e.target.value)
                 }
                 placeholder={t("providerForm.haikuModelPlaceholder", {
-                  defaultValue: "GLM-4.5-Air",
+                  defaultValue: "",
                 })}
                 autoComplete="off"
               />
@@ -224,7 +224,7 @@ export function ClaudeFormFields({
                   )
                 }
                 placeholder={t("providerForm.modelPlaceholder", {
-                  defaultValue: "claude-3-7-sonnet-20250219",
+                  defaultValue: "",
                 })}
                 autoComplete="off"
               />
@@ -245,7 +245,7 @@ export function ClaudeFormFields({
                   onModelChange("ANTHROPIC_DEFAULT_OPUS_MODEL", e.target.value)
                 }
                 placeholder={t("providerForm.modelPlaceholder", {
-                  defaultValue: "claude-3-7-opus-20250219",
+                  defaultValue: "",
                 })}
                 autoComplete="off"
               />