fix(docker): use absolute tsconfig path for api build

When pnpm --filter runs the api package build, tsc cannot find the
tsconfig.json. Use an absolute path to avoid any ambiguity about the
working directory context.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

Dockerfile

@@ -15,8 +15,8 @@ RUN mkdir -p /home/node/.cache/node/corepack
 COPY packages/ packages/
 COPY src/ src/
 RUN pnpm --filter @groombook/types build && \
-    cd packages/db && pnpm build && cd ../.. && \
-    pnpm build
+    pnpm --filter @groombook/db build && \
+    /app/node_modules/.bin/tsc -p /app
 
 # Runtime
 FROM node:20-alpine AS runner