fix(docker): use PostgreSQL and fix web node_modules symlinks

The prisma schema uses Json fields which require PostgreSQL, not SQLite.
Add postgres service to both docker-compose files and update DATABASE_URL
accordingly. Fix web Dockerfile to use pnpm deploy for flat, symlink-free
node_modules that replace the broken pnpm workspace symlinks in the
Next.js standalone output. Add OpenSSL to server runner for Prisma's
PostgreSQL engine.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

fix(docker): fix web CMD path and server broken prisma symlinks

The web Dockerfile referenced apps/web/server.js but standalone output
is at /app/server.js. The server Dockerfile copied pnpm workspace
node_modules with broken symlinks; now uses pnpm deploy --legacy for
a flat, symlink-free node_modules. Moves prisma to production deps
since it's needed at runtime for migrations.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

fix(web): prevent button text wrapping in watched folders header

Add whitespace-nowrap to Scan All and Add Folder buttons, and
shrink-0 to the button container so they don't compress and wrap.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

feat(db): switch from PostgreSQL to SQLite

Upgrade Prisma 5 → 6 for native SQLite Json field support, removing
the need for a separate PostgreSQL service. This simplifies deployment
from 6 services to 5.

- Upgrade prisma and @prisma/client to ^6.2.0
- Change schema provider to sqlite
- Remove @default("[]") from tags field (Prisma 6 SQLite bug #26571)
- Add explicit tags: [] to userBook.create calls
- Delete PostgreSQL-specific migrations
- Remove postgres service from docker-compose files
- Remove openssl dependency from server Dockerfile
- Bump version to 0.3.0

Co-Authored-By: Claude Opus 4.5 <[email protected]>

fix(parser): improve paragraph detection for better text rendering

- Extended block-level HTML element detection from 5 to 26+ elements
- Split paragraphs on double newlines (paragraph boundaries) vs single (soft breaks)
- Added whitespace-pre-line CSS to preserve line breaks within paragraphs
- Fixes books rendering without proper paragraph separation

Co-Authored-By: Claude Opus 4.5 <[email protected]>