feat(01-01): install Drizzle ORM, postgres-js, and configure DB client

- drizzle-orm@0.45.2 + postgres@3.4.9 installed (postgres-js driver)
- drizzle-kit@0.31.10 installed as dev dependency
- nanoid@5, zod@4, react-hook-form, @hookform/resolvers installed
- src/db/index.ts: Drizzle client initialized with postgres-js driver
- drizzle.config.ts: configured for postgresql dialect + src/db/schema.ts
- .env.example: added as public template (no secrets)
- .gitignore: allow .env.example while blocking all other .env* files

.gitignore

@@ -30,8 +30,9 @@ yarn-debug.log*
 yarn-error.log*
 .pnpm-debug.log*
 
-# env files (can opt-in for committing if needed)
+# env files — exclude secrets, allow public template
 .env*
+!.env.example
 
 # vercel
 .vercel