feat: implement user profile pages with comment avatar links

Added user profile feature allowing authenticated users to view profiles of other users. Key changes:

**New Routes:**
- `/users/[id]/+page.server.ts` - Server-side load function with authentication guard and user data fetching
- `/users/[id]/+page.svelte` - User profile UI component displaying avatar, stats, and bio

**Features:**
- Authentication required - redirects to /login if not authenticated
- Shows user display name (first_name + last_name or email fallback)
- Displays join date, location, and description
- Statistics: comments count and likes count
- "Edit Profile" button visible only for own profile (links to /me)
- Responsive layout with avatar placeholder for users without profile images

**Comment Integration:**
- Updated video comment section to link user avatars to their profiles
- Added hover effects on avatars (ring-primary/40 transition)
- Username in comments now clickable and links to `/users/[id]`

**Translations:**
- Added `profile` section to en.ts locales with:
  - member_since: "Member since {date}"
  - comments: "Comments"
  - likes: "Likes"
  - edit: "Edit Profile"
  - activity: "Activity"

**Design:**
- Simplified layout (no cover banner) compared to model profiles
- Peony background with card-based UI
- Primary color theme with gradient accents
- Consistent with existing site design patterns

This creates a clear distinction between:
- Model profiles (`/models/[slug]`) - public, content-focused
- User profiles (`/users/[id]`) - authenticated only, viewer-focused

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

packages/frontend/src/lib/i18n/locales/en.ts

@@ -223,6 +223,13 @@ export default {
 			toast_reset: "Your password has been reset!",
 		},
 	},
+	profile: {
+		member_since: "Member since {date}",
+		comments: "Comments",
+		likes: "Likes",
+		edit: "Edit Profile",
+		activity: "Activity",
+	},
 	models: {
 		title: "Our Models",
 		description: