feat: complete release readiness work

- consolidate API ownership and remove dead vendor code

- add Stripe billing, learning paths, and public CV hardening

- add migration, recovery, security, audit, and browser gates

JobTrackerApi/Dockerfile

@@ -3,11 +3,7 @@ FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
 WORKDIR /src
 
 COPY JobTrackerApi/JobTrackerApi.csproj JobTrackerApi/
-COPY JobTrackerBackend/JobTrackerBackend.csproj JobTrackerBackend/
-COPY Data/ Data/
-COPY Models/ Models/
 COPY JobTrackerApi/ JobTrackerApi/
-COPY JobTrackerBackend/ JobTrackerBackend/
 
 # Retry once after clearing NuGet caches. Transient download corruption on the
 # build host can trip NU3008 ("package integrity check failed / has changed since