Add dual adapter support for Node and Static builds
Enable building chat-ui with both adapter-node (web/SSR) and adapter-static
(Capacitor/Tauri SPA) from the same codebase.
Key changes:
- Refactor hooks.server.ts to use lazy dynamic imports with building checks
- Extract hook implementations to separate files under src/lib/server/hooks/
- Add building check to config.ts init() to skip database access during static builds
- Add conditional adapter selection in svelte.config.js based on ADAPTER env var
- Add build:static npm script and adapter-static dependency
Usage:
- npm run build (node adapter, default)
- npm run build:static (static adapter for SPA)
