fix(deploy): install ca-certificates in Docker builder stage for sourcemap upload

sentry-cli (Rust binary) failed the sourcemap upload with "unable to get
local issuer certificate" when talking to GlitchTip over TLS -- the
node:22-alpine builder image ships without a CA bundle. Confirmed via
verbose build log after the SENTRY_RELEASE fix resolved the prior
--release undefined failure.

docker/Dockerfile

@@ -14,6 +14,12 @@ RUN npm ci
 FROM node:22-alpine AS builder
 WORKDIR /app
 
+# sentry-cli (invoked by withSentryConfig during `npm run build` to upload
+# source maps) is a Rust binary that needs the system CA bundle to validate
+# GlitchTip's TLS cert — Alpine ships without one, causing "unable to get
+# local issuer certificate" and a failed upload.
+RUN apk add --no-cache ca-certificates
+
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .