Fix Docker build context for deployment

.dockerignore

@@ -1,17 +1,21 @@
-**/.git
-**/.vs
-**/.idea
-**/.vscode
+# Keep the backend build context as small and predictable as possible.
+# The backend Docker build uses the repo root as its context, so exclude
+# everything first and then opt back into only the source folders it needs.
+*
+!JobTrackerApi/
+!Data/
+!Models/
+!.dockerignore
 
-**/bin
-**/obj
-**/bin_build
+# Include the source trees.
+!JobTrackerApi/**
+!Data/**
+!Models/**
 
-**/*.db
-**/*.db-*
-
-job-tracker-ui/node_modules
-job-tracker-ui/build
-
-**/node_modules
-**/npm-debug.log
+# Re-exclude generated and local data inside the backend project.
+JobTrackerApi/bin/
+JobTrackerApi/obj/
+JobTrackerApi/bin_build/
+JobTrackerApi/Attachments/
+JobTrackerApi/*.db
+JobTrackerApi/*.db-*