feat: add new SCSS partials for collection and gallery components

- Added a new SCSS partial `_collection.scss` to define styles for the collection component.
- Added a new SCSS partial `_gallery.scss` to define styles for the gallery component.

The new partials contain styles for the collection and gallery components, including layout, positioning, and animations.

---

feat: add support for gallery functionality in mobile

- Created a new file `gallery.ts` to handle the gallery functionality in the mobile view.
- Added functions `slideUp()` and `slideDown()` to handle the sliding animation of the gallery.
- Initialized the gallery with the provided image data in the `initGallery()` function.
- Added event listeners to update the active slide and index text when the slide is changed.
- Created a helper function `changeSlide()` to change the active slide in the gallery.
- Created a helper function `scrollToActive()` to scroll to the active image in the collection.
- Created a helper function `updateIndexText()` to update the index text in the navigation.
- Created a helper function `createGallery()` to dynamically create the gallery HTML structure.

---

feat: add scrollable flag for mobile view

- Created a new file `scroll.ts` to handle the scrollable flag for the mobile view.
- Added a `scrollable` variable as a Watchable object to control the scrollability of the view.

---

fix: change port variable case from lowercase `port` to uppercase `PORT` to improve semantics

- Changed the variable name `port` to `PORT` in the `server.ts` file to improve code readability and semantics.
- The variable `PORT` is now used to define the port number for the server to listen on.

assets/scss/_partial/_collection.scss

@@ -0,0 +1,29 @@
+.collection {
+  display: flex;
+  flex-direction: column;
+  gap: 20vh;
+
+  padding-top: 50vh;
+  margin-top: calc(var(--nav-height) * -1);
+
+  img {
+    position: sticky;
+    top: 50vh;
+
+    width: 60vw;
+    height: 20vh;
+
+    object-fit: contain;
+
+    transform: translate3d(0, -50%, 0);
+    align-self: center;
+
+    &:last-child {
+      margin-bottom: 20vh;
+    }
+  }
+}
+
+.hidden {
+  display: none;
+}