[FEAT] Add user profile/settings page

[Priyanshu-byte-coder]

What Needs to Be Done

Create a /profile page where users can view their account info and manage settings:

• GitHub username, avatar, email
• Connected accounts (GitHub now, GitLab later)
• Option to delete account and data

Why This Matters

Users need a way to see what data is stored about them, and a place to manage integrations as we add GitLab support.

Files to Create/Modify

• src/app/profile/page.tsx — new page
• src/components/Navbar.tsx — add nav link to profile (or add to dashboard header)
• src/app/api/user/route.ts — GET current user info from Supabase
• src/app/api/user/route.ts — DELETE to remove user and all their data

Acceptance Criteria

• /profile page shows GitHub avatar, username, email
• Shows account creation date
• "Delete Account" button with confirmation dialog
• DELETE /api/user removes user + cascades to goals and snapshots
• Navigation from dashboard to profile and back
• No TypeScript errors, lint passes

Tech Context

User data stored in Supabase users table. Use getServerSession(authOptions) for auth in the API route.
For deletion: supabaseAdmin.from('users').delete().eq('github_id', session.githubId) — cascade handles goals/snapshots.

[akhila-sraj]

Hi @Priyanshu-byte-coder
I would like to work on this issue as a part of Gssoc 26
Pls assign this issue to me.