refactor: restructure src into features, domain services and component layers

[Yashh56]

What changed

• components/ reorganized into layout/, shared/, providers/, feedback/, dev/
• bridgeApi.ts split into domain service classes (DatabaseService, GitService, etc.)
• Pages reduced to thin composition, all bridge handlers moved to feature hooks
• Hooks and types co-located inside their feature folders
• components/common removed — files distributed by responsibility

Structure before → after

before: flat hooks/, flat components/common/, monolithic bridgeApi.ts
after: features/{domain}/hooks, components/{layer}, services/bridge/{domain}

What didn't change

• Zero business logic modified
• Zero UI changes
• All existing behaviour preserved

How to review

Suggested order to avoid confusion:

1. services/bridge/ — new domain services
2. components/ — new folder structure
3. features/*/hooks/ — extracted page hooks
4. pages/ — now thin composition only