feat: add Reddit share option to ShareSheet

[Mash4-4-4-4]

Description

Fixes #135

Added a new Reddit share option to the dashboard ShareSheet component so users can easily share their CommitPulse dashboards to Reddit communities like r/webdev, r/github, and other developer spaces.

Changes made

• Added a custom inline RedditIcon SVG component
• Implemented handleReddit() using Reddit's submit/share intent URL
• Added Reddit share action to the ShareSheet options array
• Added orange Reddit-themed gradient styling for visual consistency
• Fixed username propagation in ProfileCard to ensure generated share URLs correctly point to /dashboard/[username]

Result

Users can now:

• Open the ShareSheet
• Click “Share on Reddit”
• Instantly open Reddit’s submission flow with their dashboard URL prefilled

This improves social discoverability and makes sharing developer activity more accessible across community-driven platforms.

Pillar

• 🎨 Pillar 1 — New Theme Design
• 📐 Pillar 2 — Geometric SVG Improvement
• 🕐 Pillar 3 — Timezone Logic Optimization
• 🛠️ Other (Bug fix, refactoring, docs)

Visual Preview

Added a new Reddit sharing option with:

• Reddit branded icon
• Orange gradient styling
• Functional Reddit submit/share flow

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.

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[github-actions]

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Thanks for opening your first pull request — this is a big deal and we appreciate the effort!

While you wait for a review, please double-check:

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