feat: refactor skills API and database schema

- Replaced file-based skill category loading with API calls in the GET and POST methods of the skills route.
- Added new `SkillsService` for handling skill category operations.
- Updated SQL initialization script to create `skill_categories`, `skills`, and `skill_links` tables with appropriate relationships.
- Enhanced `ApiClient` with methods for loading skill categories and creating new skills, improving API interaction.
- Introduced error handling for skill category creation and loading processes.

app/api/skills/[categoryId]/route.ts

@@ -0,0 +1,55 @@
+import { NextResponse } from "next/server";
+import { SkillsService } from "@/services";
+
+interface RouteParams {
+  params: {
+    categoryId: string;
+  };
+}
+
+export async function GET(request: Request, { params }: RouteParams) {
+  try {
+    const skills = await SkillsService.getSkillsByCategory(params.categoryId);
+    return NextResponse.json(skills);
+  } catch (error) {
+    console.error("Error loading skills by category:", error);
+    return NextResponse.json(
+      { error: "Failed to load skills by category" },
+      { status: 500 }
+    );
+  }
+}
+
+export async function POST(request: Request, { params }: RouteParams) {
+  try {
+    const skillData: {
+      id: string;
+      name: string;
+      description: string;
+      icon?: string;
+      links: string[];
+    } = await request.json();
+
+    // Validate required fields
+    if (!skillData.id || !skillData.name || !skillData.description) {
+      return NextResponse.json(
+        { error: "Missing required fields: id, name, description" },
+        { status: 400 }
+      );
+    }
+
+    await SkillsService.createSkill({
+      ...skillData,
+      categoryId: params.categoryId,
+      links: skillData.links || [],
+    });
+
+    return NextResponse.json({ success: true }, { status: 201 });
+  } catch (error) {
+    console.error("Error creating skill:", error);
+    return NextResponse.json(
+      { error: "Failed to create skill" },
+      { status: 500 }
+    );
+  }
+}