Replace all 'as any' type assertions with proper TypeScript types

[georgi]

Problem

Many components use as any type assertions which bypass TypeScript's type checking and can hide bugs. These should be replaced with proper type definitions.

What to do

1. Search for all as any in web/src/ (excluding test files)
2. For each occurrence, determine the actual type and replace the assertion
3. If a proper type doesn't exist yet, create an interface or type alias
4. Common patterns to fix:
   • Event handlers: as any → as React.MouseEvent<HTMLButtonElement>
   • Store selectors: as any → proper state type
   • API responses: as any → response interface
   • Theme access: as any → as Theme

Important

• Do NOT just replace as any with as unknown — that's equally bad
• If you truly cannot determine the type, use a specific comment explaining why
• Run npm run typecheck to verify your changes compile