Summary

• add a PlatformLoopService API for approving or rejecting pending Tune proposals by proposal id
• reconstruct proposal metadata from the append-only ledger before recording the decision
• prevent duplicate decisions once a proposal has been approved, rejected, or executed

Verification

• dotnet test tests\AppLens.Backend.Tests\AppLens.Backend.Tests.csproj -c Debug --filter PlatformLoopServiceTests
• dotnet build AppLensDesktop.sln -c Debug
• dotnet test AppLensDesktop.sln -c Debug

Review lenses

• CEO: this moves AppLens toward usable consent-based Tune workflows without widening the UI branch.
• Master Dev: isolated backend change, ledger-backed tests, no overlap with PR [codex] Add AppLens module detail selection #7 or PR [codex] Run all AppLens tests in desktop CI #8.