fix: force recompile in Docker build to prevent stale BEAM files (#119)

Incremental compilation can miss schema field removals in dependent
modules, causing undefined_column errors in production.

Reviewed-on: graham/towerops-web#119

k8s/Dockerfile

@@ -80,9 +80,9 @@ RUN cd c_src && make
 
 COPY lib lib
 
-# Compile the release
+# Compile the release (--force prevents stale BEAM files from schema changes)
 RUN --mount=type=cache,target=/root/.mix \
-    mix compile
+    mix compile --force
 
 COPY assets assets