create footer component

[sumishsamina]

Adds the site footer: logo, blurb, social links, back-to-top button, ACNC charity badge, site map, and copyright bar. Includes faint house watermark background per the design.
Closes #6

Related issue

• Resolve Create Footer Component #6

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.44%. Comparing base (b578079) to head (a52b6e8).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #30   +/-   ##
=======================================
  Coverage   94.44%   94.44%           
=======================================
  Files           7        7           
  Lines          54       54           
=======================================
  Hits           51       51           
  Misses          3        3           

Flag	Coverage Δ
backend	94.44% <ø> (ø)

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[KKatariah]

You need to run the Prettier extension to fix formatting issues in the code. You can install it on VSCode.

Checking formatting...
[warn] src/components/ui/footer.tsx
[warn] Code style issues found in the above file. Run Prettier with --write to fix.
**Error:** Process completed with exit code 1.

[KKatariah]

Someone needs to fix this merge conflict I'm too tired lol