Redesign footer to match Dropcast style — centered, 'Made by @project7'

[realproject7]

Summary

Redesign the footer to match Dropcast's cleaner style. Reference `~/Projects/dropcast/components/layout/Footer.tsx`.

Changes

• Remove "PlotLink © 2026"
• Replace with: `v{version} • Base Mainnet • Made by @project7`
• "@project7" links to `https://farcaster.xyz/project7\`
• Center-align all footer content
• Match Dropcast's button/link style (clean, minimal, text-muted)
• Do NOT add PlotLink logo or tagline again — keep it simple
• Keep existing links (contract, $PLOT, github) but style them like Dropcast

Acceptance Criteria

• Footer shows version, network, and "Made by @project7"
• @project7 links to Farcaster profile
• Content centered
• Matches Dropcast footer aesthetic