fix: add slash separator and semicolon in @font-face CSS

The @fs URL prefix was concatenated directly with the font file path,
creating invalid URLS like `/@fsc:/path` insted of `/@fs/C:path`.

Additionally, the src property was missing a semicolon, causing CSS
parsing errors and preventing font requests from being made.

This caused 404 errors and font loading failures in dev mode.

Author: Chiman2937

src/plugins/next-font/local/get-font-face-declarations.ts

@@ -72,7 +72,7 @@ export async function getFontFaceDeclarations(options: LoaderOptions) {
       if ("fontReferenceId" in localFontSrc) {
         return dedent`@font-face {
 					font-family: ${id};
-					src: url(${localFontSrc.fontReferenceId ? getPlaceholderFontUrl(localFontSrc.fontReferenceId) : `/@fs${localFontSrc.fontPath}`})
+					src: url(${localFontSrc.fontReferenceId ? getPlaceholderFontUrl(localFontSrc.fontReferenceId) : `/@fs/${localFontSrc.fontPath}`});
 					${fontDeclarations}
 				}`;
       }
@@ -86,7 +86,7 @@ export async function getFontFaceDeclarations(options: LoaderOptions) {
         .map((font) => {
           return dedent`@font-face {
 						font-family: ${id};
-						src: url(${font.path.fontReferenceId ? getPlaceholderFontUrl(font.path.fontReferenceId) : `/@fs${font.path.fontPath}`});
+						src: url(${font.path.fontReferenceId ? getPlaceholderFontUrl(font.path.fontReferenceId) : `/@fs/${font.path.fontPath}`});
 						${font.weight ? `font-weight: ${font.weight};` : ""}
 						${font.style ? `font-style: ${font.style};` : ""}
 						${fontDeclarations}