Add detailed analysis and documentation for RSNet.dll download functionality

- Introduced a comprehensive markdown document outlining the API surface of RSNet.dll related to downloading video files.
- Documented initialization, connection, record querying, and download processes.
- Provided insights into the exported functions, their parameters, and expected behaviors.
- Included practical implications and recommendations for implementing a downloader script using C# interop.
- Highlighted the necessary struct layouts and callback mechanisms for effective integration with the DLL.

SurveillanceClient/.gitignore

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+# Build results
+[Bb]in/
+[Oo]bj/
+[Oo]ut/
+[Ll]og/
+[Ll]ogs/
+
+# User-specific files
+*.user
+*.suo
+*.userosscache
+*.sln.docstates
+*.rsuser
+
+# Visual Studio
+.vs/
+*.VisualState.xml
+*.pidb
+*.svclog
+
+# JetBrains Rider
+.idea/
+*.DotSettings.user
+
+# VS Code
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+
+# NuGet
+*.nupkg
+*.snupkg
+.nuget/
+packages/
+!packages/build/
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+# MSBuild Binary and Structured Log
+*.binlog
+
+# ReSharper
+_ReSharper*/
+*.[Rr]e[Ss]harper
+
+# Test results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+coverage*.json
+coverage*.xml
+coverage*.info
+
+# Local secrets / configuration overrides (NEVER COMMIT CREDENTIALS)
+appsettings.Development.json
+appsettings.Local.json
+appsettings.*.Local.json
+secrets.json
+secrets.*.json
+*.secrets
+.env
+.env.*
+
+# OS
+Thumbs.db
+ehthumbs.db
+Desktop.ini
+.DS_Store
+
+# Downloaded video output (local runtime artifact)
+downloads/
+output/