feat: Support file upload and parsing in requirements page (Fixes #95)

[sureshchouksey8]

Closes #95

[sureshchouksey8]

Validation update for linked bounty #95:

• PR adds file upload support on the project requirement/evaluation page and stores uploaded files as Markdown links/images for the follow-up evaluation message.
• Pushed a small formatting follow-up in 040b043 after rechecking the touched files.
• Local validation that passed:
  • NPM_CONFIG_USERCONFIG=/dev/null npx -y prettier@3.8.0 --no-config --single-quote --trailing-comma all --arrow-parens avoid --tab-width 2 --print-width 100 --check models/File.ts 'pages/dashboard/project/[id].tsx'
  • git diff --check
• Full dependency install/typecheck could not be completed in this local environment because pnpm install --ignore-scripts is blocked by GitHub Packages access for @idea2app/data-server@1.0.0-rc.9 with 403.

Current PR head is 040b0434794b35359f6c38d2505be711b095175b; GitHub reports the PR as open, non-draft, and mergeable.