fix: use npm install instead of npm ci (no lockfile in repo)

Also unignore package-lock.json for future deterministic installs.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,5 @@
 # Dependencies
 node_modules/
-package-lock.json
 yarn.lock
 pnpm-lock.yaml
 

Dockerfile

@@ -4,7 +4,7 @@ FROM node:20-alpine AS frontend-builder
 WORKDIR /frontend
 
 COPY frontend/package*.json ./
-RUN npm ci
+RUN npm install
 
 COPY frontend/ ./
 
@@ -18,7 +18,7 @@ FROM node:20-alpine AS backend-builder
 WORKDIR /app
 
 COPY backend/package*.json ./
-RUN npm ci
+RUN npm install
 
 COPY backend/tsconfig.json ./
 COPY backend/src ./src
@@ -32,7 +32,7 @@ WORKDIR /app
 
 # Copy backend production deps
 COPY backend/package*.json ./
-RUN npm ci --omit=dev
+RUN npm install --omit=dev
 
 # Copy compiled backend
 COPY --from=backend-builder /app/dist ./dist