feat(validation): relax Instagram URL validation to support all content types

- Create validateInstagramUrl utility using URL constructor
- Replace regex-based validation with hostname and protocol checks
- Support posts, reels, IGTV, and URLs with query parameters
- Add comprehensive unit tests (22 tests, all passing)
- Add integration tests for new URL formats
- Update API documentation with supported URL formats

Closes: #RelaxInstagramUrlValidation

src/tests/queue-api.spec.ts

@@ -71,10 +71,72 @@ describe('Queue API Endpoints', () => {
       expect(item?.url).toBe('https://www.instagram.com/p/XYZ789');
     });
     
+    it('should accept Instagram reel URLs', async () => {
+      const request = new Request('http://localhost/api/queue', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          url: 'https://instagram.com/reel/ABC123'
+        })
+      });
+      
+      const response = await queuePOST({ request } as any);
+      expect(response.status).toBe(200);
+      const data = await response.json();
+      expect(data.url).toBe('https://instagram.com/reel/ABC123');
+    });
+
+    it('should accept Instagram URLs with query parameters', async () => {
+      const request = new Request('http://localhost/api/queue', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          url: 'https://www.instagram.com/reel/DSevV5CDcNm/?utm_source=ig_web_copy_link'
+        })
+      });
+      
+      const response = await queuePOST({ request } as any);
+      expect(response.status).toBe(200);
+      const data = await response.json();
+      expect(data.url).toBe('https://www.instagram.com/reel/DSevV5CDcNm/?utm_source=ig_web_copy_link');
+    });
+
+    it('should accept Instagram IGTV URLs', async () => {
+      const request = new Request('http://localhost/api/queue', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          url: 'https://instagram.com/tv/XYZ789'
+        })
+      });
+      
+      const response = await queuePOST({ request } as any);
+      expect(response.status).toBe(200);
+    });
+
+    it('should reject HTTP (non-HTTPS) URLs', async () => {
+      const request = new Request('http://localhost/api/queue', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          url: 'http://instagram.com/p/ABC123'
+        })
+      });
+      
+      try {
+        const response = await queuePOST({ request } as any);
+        expect(response.status).toBe(400);
+        const data = await response.json();
+        expect(data.message).toContain('HTTPS');
+      } catch (err: any) {
+        expect(err.status).toBe(400);
+        expect(err.body.message).toContain('HTTPS');
+      }
+    });
+    
     it('should reject invalid Instagram URL formats', async () => {
       const invalidUrls = [
         'https://facebook.com/post/123',
-        'https://instagram.com/user/profile', 
         'not-a-url',
         'https://other-site.com'
       ];
@@ -93,11 +155,12 @@ describe('Queue API Endpoints', () => {
           // If we get here, check the response status
           expect(response.status).toBe(400);
           const data = await response.json();
-          expect(data.message).toBe('Invalid Instagram URL format. Expected: https://instagram.com/p/{post-id}');
+          // Updated to check for new error messages
+          expect(data.message).toBeTruthy();
         } catch (err: any) {
           // SvelteKit's error() throws - check the error
           expect(err.status).toBe(400);
-          expect(err.body.message).toBe('Invalid Instagram URL format. Expected: https://instagram.com/p/{post-id}');
+          expect(err.body.message).toBeTruthy();
         }
       }
       
@@ -105,6 +168,33 @@ describe('Queue API Endpoints', () => {
       expect(queueManager.getAll()).toHaveLength(0);
     });
     
+    it('should reject non-Instagram domains', async () => {
+      const invalidUrls = [
+        'https://facebook.com/post/123',
+        'https://twitter.com/status/456',
+        'https://example.com',
+        'https://instagram.com.evil.com/p/123'
+      ];
+      
+      for (const url of invalidUrls) {
+        const request = new Request('http://localhost/api/queue', {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ url })
+        });
+        
+        try {
+          const response = await queuePOST({ request } as any);
+          expect(response.status).toBe(400);
+          const data = await response.json();
+          expect(data.message).toContain('instagram.com');
+        } catch (err: any) {
+          expect(err.status).toBe(400);
+          expect(err.body.message).toContain('instagram.com');
+        }
+      }
+    });
+    
     it('should reject missing URL', async () => {
       const request = new Request('http://localhost/api/queue', {
         method: 'POST',