Fix Docker build issues

- Add git to build dependencies (required by some npm packages)
- Add build-time environment variables (NEXT_PUBLIC_VAPID_PUBLIC_KEY, BETTER_AUTH_SECRET, BETTER_AUTH_URL)
- Add error output capture (2>&1) to expose build errors
- Ensure all dependencies are available during build phase

Dockerfile

@@ -5,21 +5,26 @@ WORKDIR /app
 
 # Install dependencies stage
 FROM base AS deps
-RUN apk add --no-cache libc6-compat
+RUN apk add --no-cache libc6-compat git
 COPY pnpm-lock.yaml pnpm-workspace.yaml package.json ./
 RUN pnpm install --frozen-lockfile --prod
 
 # Build stage
 FROM base AS builder
-RUN apk add --no-cache libc6-compat postgresql-client
+RUN apk add --no-cache libc6-compat git postgresql-client
 COPY pnpm-lock.yaml pnpm-workspace.yaml package.json ./
 RUN pnpm install --frozen-lockfile
 
 # Copy source code
 COPY . .
 
+# Set required build-time environment variables
+ENV NEXT_PUBLIC_VAPID_PUBLIC_KEY=dummy_key_for_build
+ENV BETTER_AUTH_SECRET=dummy_secret_for_build
+ENV BETTER_AUTH_URL=http://localhost:3000
+
 # Build the app
-RUN pnpm build
+RUN pnpm build 2>&1
 
 # Production runtime
 FROM base AS runtime