feat(dashboard): persist GoalTracker goals in MongoDB for cross-device synchronization

[kanishka-2007-tech]

Description

This PR migrates GoalTracker persistence from browser-only localStorage to the existing server-side user storage.

Previously, monthly and yearly contribution goals were stored exclusively using useLocalStorage. As a result, users would lose their goals when:

Switching to a different device
Using another browser
Clearing browser storage
Opening the dashboard in private/incognito mode

Since users are already identified by their GitHub username and the project already includes a MongoDB-backed User model, goals are now synchronized with the user's account, ensuring they persist across sessions and devices.

Fixes #8276

Pillar

• 📐 Pillar 2 — Geometric SVG Improvement
• 🕐 Pillar 3 — Timezone Logic Optimization
• 🛠️ Other (Bug fix, refactoring, docs)

Checklist before requesting a review:

• I have read the CONTRIBUTING.md file.
• I have tested these changes locally (localhost:3000/api/streak?user=YOUR_USERNAME).
• I have run npm run format and npm run lint locally and resolved all errors (CI will fail otherwise).
• My commits follow the Conventional Commits format (e.g., feat(themes): ..., fix(calculate): ...).
• I have updated README.md if I added a new theme or URL parameter.
• I have started the repo.
• I have made sure that i have only one commit to merge in this PR.
• The SVG output matches the CommitPulse "premium quality" aesthetic standard (no raw elements, smooth animations, correct fonts).
• (Recommended) I joined the CommitPulse Discord community for contributor discussions, mentorship, and faster PR support.

[vercel]

@kanishka-2007-tech is attempting to deploy a commit to the jhasourav07's projects Team on Vercel.

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[retenta-bot]

This pull request addresses the critical issue of user goals being lost when switching devices or clearing browser storage by implementing server-side persistence with MongoDB. This aligns with previous decisions made to sync contribution goals with MongoDB, ensuring a seamless user experience. Thank you for your contribution, and I look forward to your updates!

[github-actions]

📦 Next.js Bundle Size Report (Gzipped Sizes)

Asset	PR Size	Base Size	Difference	Status
static/chunks/app/(root)/dashboard/[username]/page-[hash].js	54.18 KB	54.03 KB	+0.15 KB (+0.28%)	🔴 Regression
static/chunks/app/api/user/goals/route-[hash].js	0.26 KB	-	+0.26 KB (++100%)	🆕 New

📊 Summary of Totals

Category	PR Size	Base Size	Difference
Total JS	4053.84 KB	4052.50 KB	+1.34 KB (+0.03%)
Total CSS	338.94 KB	338.94 KB	0 B

[Aamod007]

The MongoDB persistence layer for GoalTracker goals is well-architected — clean API routes with proper validation (parseGoals with range checks), CSRF protection, and graceful fallback when MONGODB_URI is unset. The GoalTracker component's sync logic with server round-trip is sound.

CI is failing though. Please check the logs and push fixes so we can proceed.

Labels: level:intermediate (3 files, API+model+component changes), quality:clean, type:feature, mentor:Aamod007

[Aamod007]

Re-reviewing after noting the only CI failure is Vercel authorization (not code-related). All other checks (Format · Lint · Typecheck · Test, Production Build, CodeQL) pass. Approving — the Vercel deploy auth is a repo-level config issue, not a code problem.