fix: log Prisma connection status on startup

[harshitaaa0]

Description

During local development it wasn't obvious whether Prisma had connected successfully — there was no startup log confirming a healthy connection, and failures only surfaced later as confusing errors on the first database query.

The root cause was that PrismaClient was being instantiated separately in 23 different files across the codebase (nearly every route, plus a couple of services). With connections scattered like this, there was no single place to check or log connection status, and as a side effect every dev hot-reload spun up a new, un-closed connection pool.

This PR:

• Adds app/utils/db.server.ts, a single shared Prisma client that calls $connect() explicitly on startup and logs a clear ✅ success message, or a ❌ message with actionable next steps (check DATABASE_URL/DIRECT_URL, confirm the database is reachable, re-run npx prisma generate) if the connection fails
• Caches the client on globalThis in development so hot-reloads reuse the same connection instead of leaking new ones
• Updates all 23 files that previously ran new PrismaClient() to import the shared client from ~/utils/db.server instead

Logging in only one of many scattered clients wouldn't reflect the app's real connection state, so consolidating to a single shared client was necessary to make the logging meaningful — this also resolves a related connection-pool leak in dev.

prisma/seed.ts and scripts/create-demo-user.ts are standalone one-off scripts and were intentionally left untouched.

Related Issues

Fixes #<#83>

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

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