Add 180 and 270-degree rotation blocks

Summary

Add 180-degree and 270-degree screen rotation blocks to accommodate various mirrored or turned monitor setups.

Reader/display rotation supports 180-degree and 270-degree orientations.
Rotation controls work with mirrored or physically turned monitor setups without clipping primary reader content.
Add or update browser/UI test coverage for the relevant user flow.
Solution tests pass before the issue is marked ready for user verification.

@byskyphy

Implemented in 8973309 and pushed to main.

What changed:

Added full reader/display orientation cycling: landscape -> 90° portrait -> 180° inverted -> 270° portrait -> landscape.
Synced text and camera background transforms for 180° and 270°, including mirrored setups.
Added browser/UI coverage for the orientation cycle and 270° mirrored layout containment.

Verification passed locally:

dotnet build ./PrompterOne.slnx -warnaserror --no-restore
dotnet test @./tests/dotnet-test-progress.rsp --project ./tests/PrompterOne.Web.Tests/PrompterOne.Web.Tests.csproj -- --treenode-filter "///TeleprompterPersistenceTests/|///TeleprompterControlRailTests/"
dotnet test @./tests/dotnet-test-progress.rsp --project ./tests/PrompterOne.Web.UITests.Reader/PrompterOne.Web.UITests.Reader.csproj
dotnet test @./tests/dotnet-test-progress.rsp --project ./tests/PrompterOne.Web.Tests/PrompterOne.Web.Tests.csproj
dotnet test @./tests/dotnet-test-progress.rsp --solution ./PrompterOne.slnx (1178/1178 passed)

@byskyphy please review when you have a chance.