[codex] Add one-click Markdown capture runner

[cody257]

Summary

• Add one-click AppLens capture runners for Windows and macOS/Linux.
• Route AppLens and AppLens-Tune outputs into a single Desktop capture folder.
• Switch user-facing reports from .txt to structured .md files while keeping diagnostic logs as .txt.
• Update README usage and output docs.

Why

The capture workflow needs to be simple enough for non-technical users: download, extract, double-click, send the resulting folder. Markdown reports also give AppLens-LLM a more consistent intake contract for future report ingestion and training/eval data preparation.

Validation

• python -m py_compile .\AppLens.py .\AppLens-Tune.py
• cmd /c "Run-AppLens-Capture.bat < NUL"
• Verified the capture folder contains AppLens_Results_DESKTOP-KEANRHT.md, AppLens_Tune_Results_DESKTOP-KEANRHT.md, README-What-To-Send.md, and text logs, with no stale *Results*.txt reports.
• dotnet test .\tests\AppLens.Backend.Tests\AppLens.Backend.Tests.csproj -> 19 passed.

[cody257]

Closing this draft as superseded by PR #3, which establishes the platform-ledger baseline on main. Capture-runner details can be salvaged later if they still fit the desktop/platform direction.