Fix URL truncation from bash \${VAR:=default} with braces

Deployed build had MAP_TILE_URL truncated to 'https://.../tile/{z' —
Leaflet then URL-encoded it to '%7Bz' and fetched garbage tile paths.
Root cause: build-docker.sh used

    : "\${MAP_TILE_URL:=https://flights.test.aeroflot.ru/map/api/tile/{z}/{x}/{y}.jpeg}"

and bash parameter expansion terminates the default value at the
FIRST unescaped '}', leaving '{z' and discarding the rest. The env
passed to `pnpm build:standalone` was already truncated, so every
downstream step (base64 encode → HTML inject → client decode) faithfully
carried the broken value through.

Fix by moving the defaults to Dockerfile's ARG lines — ARG defaults
are plain strings, not shell-parsed — and simplify build-docker.sh to
only forward MAP_TILE_URL / API_BASE_URL as --build-arg when the
caller explicitly sets them. Quote the k8s env values for defensive
YAML hygiene as well.

Dockerfile.react

@@ -20,13 +20,20 @@ COPY src/ src/
 # broken backgrounds, missing tile icons).
 COPY config/ config/
 
-# Runtime-tunable env vars. modern.config.ts reads these when Modern.js
-# boots the SSR server at container start, so values set via k8s env
-# propagate without a rebuild. The ARG line lets CI also bake a value
-# into the image if the cluster can't set env at runtime.
-ARG MAP_TILE_URL
+# Public env values baked into dist/standalone/html/main/index.html by
+# modern.config.ts at build time. Defaults target the devwebzavod cluster
+# (no /map/api/** or /api/** ingress rule → hit the upstream that the
+# real Aeroflot ingress terminates). Production overrides via
+# --build-arg, e.g.
+#   --build-arg MAP_TILE_URL=/map/api/tile/{z}/{x}/{y}.jpeg
+#   --build-arg API_BASE_URL=/api
+# Defaults live here rather than in deployment/build-docker.sh because
+# bash `${VAR:=default}` stops at the first unescaped `}` — the literal
+# `{z}/{x}/{y}` in the URL was being truncated to `{z`. Dockerfile ARG
+# defaults are plain strings, no shell parsing.
+ARG MAP_TILE_URL=https://flights.test.aeroflot.ru/map/api/tile/{z}/{x}/{y}.jpeg
 ENV MAP_TILE_URL=${MAP_TILE_URL}
-ARG API_BASE_URL
+ARG API_BASE_URL=https://flights.test.aeroflot.ru/api
 ENV API_BASE_URL=${API_BASE_URL}
 
 RUN pnpm build:standalone