Fix all 45 audited bugs from bug-fixes.md

Verified every finding against the code, then fixed correctness (redirects,
advancement reset, duplicate heats, high-jump attempt entry, placement
ranking with tie handling, delete-dependency 500s), security (secrets out of
config, config-driven admin seed, login lockout, role authorization with
school scoping, heat-time IDOR, forwarded headers, last-admin guards),
schema integrity (nullable+filtered ExistingStudentId, unique indexes for
rounds/heats/bar heights via SchemaIntegrityFixes migration), performance
(N+1 removal in high jump/reports/standings/dashboard, SQL-side student
paging), and hygiene (duplicate notifications, auto-dismiss scope, local
bootstrap-icons, orphaned files, test-data.sql tournament creation).

FluentValidation is now registered; AutoMapper bumped to 14.0.0 (advisory
fully patched only in licence-changed 15.1.1 — documented). 11 new tests;
63/63 passing. Credential rotation and deploy-time DB_CONNECTION_STRING are
required manual follow-ups, documented in bug-fixes.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -2,8 +2,6 @@ FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
 
 WORKDIR /src
 
-EXPOSE 80
-
 # Copy project files and restore dependencies
 COPY src/SportsDivision.Domain/SportsDivision.Domain.csproj src/SportsDivision.Domain/
 COPY src/SportsDivision.Application/SportsDivision.Application.csproj src/SportsDivision.Application/
@@ -23,6 +21,8 @@ WORKDIR /app
 ENV ASPNETCORE_ENVIRONMENT=Production
 ENV ASPNETCORE_URLS=http://+:80
 
+EXPOSE 80
+
 COPY --from=build /app/out .
 
 ENTRYPOINT ["dotnet", "SportsDivision.Web.dll"]