feat: implement programmatic SEO solutions hub

- Add /solutions hub page with 10 category cards
- Add /solutions/by-concern directory page
- Add /solutions/by-oil directory page
- Add Solutions section to Footer with navigation links
- Add Breadcrumb component for solution pages
- Add translations for all solution pages (sr, en, de, fr)
- Fix ExitIntentDetector JSON parsing error
- Update sitemap with solution pages
- Create 3 sample solution pages with data files

src/lib/programmatic-seo/dataLoader.ts

@@ -0,0 +1,79 @@
+import { readFile } from "fs/promises";
+import { join } from "path";
+import type { 
+  OilForConcernPage,
+  LocalizedSEOKeywords
+} from "./types";
+
+const DATA_DIR = join(process.cwd(), "data");
+
+export function getLocalizedString(
+  localized: { sr: string; en: string; de: string; fr: string },
+  locale: string
+): string {
+  return localized[locale as keyof typeof localized] || localized.en;
+}
+
+export function getLocalizedArray(
+  localized: { sr: string[]; en: string[]; de: string[]; fr: string[] },
+  locale: string
+): string[] {
+  return localized[locale as keyof typeof localized] || localized.en;
+}
+
+export function getLocalizedKeywords(
+  seoKeywords: LocalizedSEOKeywords,
+  locale: string
+): string[] {
+  const keywords = seoKeywords[locale as keyof LocalizedSEOKeywords] || seoKeywords.en;
+  return [...keywords.primary, ...keywords.secondary, ...keywords.longTail];
+}
+
+export async function getOilForConcernPage(slug: string): Promise<OilForConcernPage | null> {
+  try {
+    const filePath = join(DATA_DIR, "oil-for-concern", `${slug}.json`);
+    const content = await readFile(filePath, "utf-8");
+    return JSON.parse(content) as OilForConcernPage;
+  } catch (error) {
+    console.error(`Failed to load oil-for-concern page: ${slug}`, error);
+    return null;
+  }
+}
+
+export async function getAllOilForConcernSlugs(): Promise<string[]> {
+  try {
+    const { readdir } = await import("fs/promises");
+    const dirPath = join(DATA_DIR, "oil-for-concern");
+    const files = await readdir(dirPath);
+    return files
+      .filter((file) => file.endsWith(".json"))
+      .map((file) => file.replace(".json", ""));
+  } catch (error) {
+    console.error("Failed to load oil-for-concern slugs:", error);
+    return [];
+  }
+}
+
+export async function getAllOilForConcernPages(): Promise<OilForConcernPage[]> {
+  const slugs = await getAllOilForConcernSlugs();
+  const pages = await Promise.all(
+    slugs.map((slug) => getOilForConcernPage(slug))
+  );
+  return pages.filter((page): page is OilForConcernPage => page !== null);
+}
+
+export async function getAllSolutionSlugs(): Promise<Array<{ locale: string; slug: string }>> {
+  const slugs = await getAllOilForConcernSlugs();
+  const result: Array<{ locale: string; slug: string }> = [];
+  
+  for (const slug of slugs) {
+    for (const locale of ["sr", "en", "de", "fr"] as const) {
+      result.push({
+        locale,
+        slug
+      });
+    }
+  }
+  
+  return result;
+}